JP2006110237A - Sewing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sewing machine suppressing cost and executing a precise sewing without deviating the height of an intermediate presser. <P>SOLUTION: A control part 6 is provided with a function of raisingly moving the intermediate presser 2 for every finish of a series of sewing operation and, when a position detecting sensor 5 detects a detection object part (a gobo 53) during moving to a waiting position, correcting an original point based on the detection position. That is to say, the control part is provided with the function of transmitting a pulse signal to a pulse motor 41 to raise the intermediate presser 2 at every time of finishing a series of sewing operation based on sewing pattern data stored in ROM 63 and RAM 62, and, as soon as the reaching of the intermediate presser 2 in the waiting position is detected by the position detection sensor 5 during rising of the intermediate presser 2, controlling to newly determine the original position based on the number of pulses of the pulse motor 41 at that time. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a sewing machine, and more particularly, to a sewing machine that performs pattern formation sewing such as embroidery.

  In a sewing machine that performs pattern formation sewing according to sewing data that has been input in advance, such as embroidery sewing, the workpiece to be sewn that is held by the outer frame and moved in the horizontal direction (XY direction) A “medium presser” of the sewing machine is known as a member for pressing the sewing product so as not to move up with the sewing needle.

This intermediate presser moves up and down in synchronization with the sewing needle with an amplitude smaller than that of the sewing needle on the upper side of the sewing product, thereby pressing the sewing product downward when the sewing needle is pulled out of the sewing product. It is formed to be retractable upward so as not to hinder the replacement of the sewing object.
By the way, in the pattern formation sewing of the sewing machine, the cloth thickness of the material to be sewn is not necessarily uniform, and when a plurality of materials to be sewn are overlapped, a step is generated on the surface of the material to be sewn. It is necessary to adjust the lowermost position in the middle.

For this reason, there is known a sewing machine that can be adjusted to the lowest position of the intermediate presser by rotating (manually rotating) a dial that is connected to the intermediate presser drive mechanism and that is provided above the sewing machine arm. (For example, refer to Patent Document 1). However, since the intermediate presser height adjustment dial is manually operated, this intermediate presser device cannot respond in real time to the change in the thickness of the workpiece being sewn. For this reason, the dial operation is driven by a pulse motor, and the operation of raising / lowering the intermediate presser to the standby position can be driven by a solenoid or air cylinder so that the sewing pattern can be changed even during the sewing operation. Accordingly, a sewing machine has been developed that can adjust the height position of the lowermost end of the intermediate presser (see, for example, Patent Document 2).
Japanese Patent Laid-Open No. 9-253365 JP 7-178272 A

However, the intermediate presser shown in Patent Document 2 is driven by a pulse motor to adjust the height of the intermediate presser during the sewing operation, and is also driven by a solenoid to move upward to the standby position. Since the two actuators are used as a drive source for adjusting the height of the actuator, there is a problem of high cost. Furthermore, since the pulse motor is employed as the intermediate presser height adjusting means, there is a problem that the pulse motor is stepped out by receiving an external force during the sewing operation.
Here, “step-out” means that a deviation occurs in the reference origin at the time of rotation in a pulse motor in which the amount of rotation is determined according to the number of applied pulse signals.
The “standby position” is a position where the intermediate presser waits when not sewing, and is an upper position in the movable range of the intermediate presser in the vertical direction. In other words, the position is sufficiently raised so that the sewing object can be easily replaced when not sewn.

  In view of the above, an object of the present invention is to provide a sewing machine capable of suppressing the cost and performing accurate sewing without causing a shift in the height of the intermediate presser.

  In order to solve the above-mentioned problem, the invention according to claim 1 is configured to synchronize with the needle, and an intermediate presser that regulates the ascent of the sewing object as the needle is raised by moving up and down in synchronization with the needle. Intermediate presser driving means for driving the intermediate presser up and down, height adjusting means capable of adjusting the height of the bottom dead center in the vertical movement of the intermediate presser, and detecting means for detecting arrival when the intermediate presser is raised And a control means capable of driving and controlling the height adjusting means, wherein the height adjusting means adjusts the height of the bottom dead center position of the intermediate presser during a sewing operation, and the intermediate presser is in the standby state. Both of the operations to rise to the position can be driven by a single pulse motor, and the control means raises the intermediate presser toward the standby position at the end of a series of sewing operations, and the detection means The pulse mode is determined from the height of the intermediate presser at the time of detection. A sewing machine and performs the origin correction processing.

According to the first aspect of the present invention, the pulse motor is driven and controlled by the control means provided in the sewing machine so that the intermediate presser moves up to the standby position located above the sewing position at the end of a series of sewing operations. Then, while raising the intermediate presser toward the standby position, it is confirmed by the control means whether or not the intermediate presser has reached a predetermined height. Further, control is performed to perform origin correction processing for determining the origin of the pulse motor based on the height of the intermediate presser at the time point detected by the detection means.
The “predetermined height” may coincide with the standby position. If they do not coincide with each other, after detecting that the predetermined height has been reached, control is performed so as to drive to a standby position by driving a known number of pulses therefrom.
In addition, “a series of sewing operations” refers to a group of sewing operations until it is necessary to reattach or replace the workpiece.
“Origin correction processing” means driving for adjusting the height of the intermediate presser and determining an origin serving as a reference point for a pulse motor that is rotationally driven in accordance with the number of input pulse signals.

  According to a second aspect of the present invention, in the sewing machine according to the first aspect, the control means is reached by the detection means each time the pulse motor rotates by one pulse when the intermediate presser is raised to the standby position. It is characterized in that control for confirming the presence or absence of is performed.

  According to the second aspect of the present invention, at the end of a series of sewing operations, the intermediate presser corresponds to one pulse of the pulse motor that applies the upward driving force to the intermediate presser by the control means provided in the sewing machine. Control is performed so as to repeatedly confirm whether or not the intermediate presser has been raised to the standby position every time the distance rises. If the intermediate presser continues to rise while repeating the raising of the intermediate presser and the confirmation operation by the detection means for each pulse, and the detection means detects that the intermediate presser has been raised to the standby position, the intermediate presser at that point in time is detected. Control is performed so that the origin of the pulse motor is determined based on the height of the pulse motor.

  According to a third aspect of the present invention, in the sewing machine according to the first aspect, the control means causes the intermediate presser to be moved by the detecting means after the intermediate presser has been lifted by an amount corresponding to the prescribed number of pulses of the pulse motor. Control is performed to confirm whether or not the vehicle has moved up to the standby position.

  According to the third aspect of the present invention, the control means does not check the height position of the intermediate presser by the detecting means until the intermediate presser is raised by an amount corresponding to the specified number of pulses of the pulse motor. After the distance corresponding to the number has passed, it is controlled so that whether or not the intermediate presser has been raised to the standby position height is confirmed by the detecting means.

  According to a fourth aspect of the present invention, in the sewing machine according to any one of the first to third aspects, the control means rotates the pulse motor by an amount corresponding to a predetermined allowable number of pulses. Even if it exists, when it is not detected by the said detection means that the said intermediate presser is raising to the said predetermined height position, control which performs an error process is performed.

In the invention according to claim 4, the control means raises the intermediate presser to the standby position after sewing, and the intermediate presser is raised to the standby position by the detecting means even after the allowable number of pulses has been exceeded. If it is not confirmed, it is controlled to perform error processing.
The “allowable number of pulses” is the number of pulses that exceeds the normal number of pulses required for the intermediate presser to rise from the sewing position to the standby position, and moves within the movable range of the intermediate presser in the vertical movement. An appropriate value that sufficiently exceeds the number of pulses required for the operation.
“Error processing” means that the number of pulses input by the control means greatly exceeds, for example, the predetermined number of pulses described above (the number of pulses necessary for the intermediate presser to rise from the sewing position to the standby position). Even if it is a case, it means a process of notifying the user that there is an abnormality when the detection means does not detect that the intermediate presser has been raised to the standby position, for example, sounding an alarm, A process of providing an error display by providing a display means.

  According to the first aspect of the present invention, the origin correction can be performed on the basis of the detection position by the detection means every time sewing is performed by the control means provided in the sewing machine. Therefore, even if the pulse motor is out of step due to, for example, the motor rotating by manual operation or an excessive external force being applied while the sewing machine is stopped or sewed, The pulse motor is corrected to the correct original point before sewing, and the next sewing operation can be performed accurately without deteriorating the quality of sewing by shifting the bottom dead center position of the intermediate presser.

  According to the second aspect of the present invention, when the intermediate presser moves up to the standby position, it is detected each time the intermediate presser is raised by a distance corresponding to one pulse of the pulse motor that applies a driving force to the intermediate presser. Since it is controlled by the means to check whether or not the intermediate presser has reached the standby position, the detection by the detection means can be performed more reliably, and the origin correction process of the pulse motor can be performed reliably. it can. Therefore, accurate sewing can be performed at the next sewing.

  According to the third aspect of the invention, the same effect as that of the first aspect of the invention can be obtained, and in particular, the height of the intermediate presser can be confirmed by the detecting means when the intermediate presser is a predetermined distance. Since it is performed after lifting (that is, after the pulse motor has rotated by the rotation angle corresponding to the specified number of pulses), it is not necessary to set a speed limit considering the detection by the detection means until the specified number of pulses. You can speed up. Therefore, accurate sewing can be performed at the next sewing, and the cycle time of the sewing operation can be shortened.

  According to the invention described in claim 4, it is confirmed by the control means that the intermediate presser has been raised to the standby position by the detection means even after the pulse motor has been rotationally driven by an amount corresponding to the allowable number of pulses. If not, the control is performed so as to perform error processing, so that it is possible to detect abnormalities such as malfunctions and failures. It should be noted that a function for performing origin correction processing after the return operation is performed by error processing may be provided. Thereby, the shift of the bottom dead center position of the intermediate presser can be prevented, and accurate sewing can be performed at the next sewing.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

<First Embodiment>
The sewing machine 1 according to the present embodiment moves up and down in synchronization with the sewing needle, so that when the sewing needle is pulled out of the cloth that is the sewing object, the intermediate presser 2 that restricts the rising of the cloth, and the intermediate presser 2 has a sewing needle. The intermediate presser driving means 3 for applying a driving force for moving up and down in synchronization with the height adjustment of the bottom dead center position in the vertical movement during sewing of the intermediate presser 2 and the up / down operation to the standby position A height adjusting means 4 for applying a driving force, a position detecting sensor 5 as a detecting means capable of detecting whether or not the intermediate presser 2 has reached the standby position, and a control means capable of driving the height adjusting means 4. A control unit 6, an unillustrated outer presser and an outer presser drive mechanism (not shown) capable of holding the cloth during sewing and freely moving the cloth in the horizontal direction with respect to the sewing machine bed 101 according to the sewing data stored in the control unit 6. It is equipped with.

(Medium presser foot)
A through hole (not shown) through which a needle that moves up and down during sewing can pass is formed at one end (lower end) of the intermediate presser 2. The other end (upper side) is connected to an intermediate press driving means 3 to be described later via an intermediate presser bar, whereby the intermediate presser 2 can be reciprocated up and down.

(Intermediate presser drive means)
The intermediate presser driving means 3 has a swing shaft that is swung by obtaining a driving force from a main shaft driven by a sewing machine motor (not shown) on one end side via an eccentric cam and a connection link. The proximal end side of the intermediate presser adjusting arm 31 is fixed to the other end side of the swing shaft by a screw 30a. One end of the link 32 is fixed to a desired position of the arc-shaped elongated hole 31a formed in the intermediate presser adjusting arm 31 by an adjusting nut 32a and a step screw 32b. The other end of the link 32 is rotatably connected to the length of the link 33 by a step screw 34.
The intermediate presser positioning link 35 is rotatably fixed to a sewing machine frame (not shown) by a step screw 35a at an intermediate position in the length direction. The position of the intermediate presser 5a is lowered by the intermediate presser 5a. It corresponds to the position of the step screw 34 when it is at the dead point (state of FIG. 1). A spring hook 36 is attached to one end side of the intermediate presser positioning link 35, and a coil spring 38 is hooked between the spring hook 36 and a spring hook 37 fixed to a sewing machine frame (not shown). The intermediate presser positioning link 35 is urged to be pulled down. An intermediate presser stopper 45 is fixed to the other end side of the intermediate presser positioning link 35 and is rotatably inserted into a round hole formed on one end side of the intermediate presser link 33.
The other end side of the intermediate presser link 33 is rotatably connected to one end side of the intermediate presser link 39 by a step screw 39a. Further, the other end side of the intermediate presser link 39 and the intermediate presser link relay plate 70 are rotatably connected by a step screw 39b. The base end side of the intermediate presser bar 72 is fixed to the intermediate presser bar holder 71 with screws 73, and the intermediate presser link relay plate 70 and the intermediate presser bar holder 71 are fixed with screws. An intermediate presser 5 is fixed to the tail end side of the intermediate presser bar 72 with a screw 75.

(Height adjustment device)
The height adjusting device 4 includes a pulse motor 41 that applies a driving force related to the height adjustment of the intermediate presser 2. The pulse motor 41 is fixed to the upper position of the arm portion 103 with the output shaft directed downward, and the output shaft penetrates the arm portion 103 so as to be rotatable and protrudes into the arm portion 103. . The distal end portion of the output shaft is connected to one end portion of the adjustment shaft 42 formed in a screw shape so as to be integrally rotatable. The other end portion of the adjustment shaft 42 is formed on the upper portion of the adjustment member 43. It is screwed in freely by a screw action. The lower part of the adjustment member 43 is in contact with the intermediate presser stopper 45. Further, one side portion of the adjusting member 43 is engaged with a groove 44 formed in the inner wall portion of the arm portion 103 so as to extend in a substantially vertical direction, whereby rotation of the shaft center is restricted, and the groove 44 is slidable in the vertical direction.
Then, by rotating and driving the pulse motor 41, the adjustment shaft 42 is rotated, the lower end portion of the adjustment shaft 42 is screwed, and the adjustment member 43 whose rotation about the shaft center is restricted is caused in the axial direction by the screw action. It can be fixed by adjusting the height of the tip that moves and contacts the intermediate press stopper 45 as desired. As a result, the height of the intermediate presser stopper 45 serving as the center of rotation of the intermediate presser link 33 can be adjusted. Further, the height adjustment of the bottom dead center position of the intermediate presser 2 during the sewing operation can be performed. Both the operation of raising the intermediate presser 2 to the standby position can be driven by one pulse motor 41.
The pulse motor 41 is rotated forward and backward based on a pulse signal sent from the control unit 6 described later, and the amount of rotation is determined in proportion to the number of pulse signals sent from the control unit 6. . That is, since the rotation amount of the pulse motor 41 and the rising amount (or lowering amount) of the intermediate presser 2 are in a proportional relationship, the number of pulses output to the pulse motor 41 and the rising amount (or lowering amount) of the intermediate presser 2 are set. Needless to say, it has become proportional.

(Position detection sensor 5)
As shown in FIG. 1, the position detection sensor 5 includes a light shielding plate 53 that is fixedly mounted on an intermediate presser bar that is moved up and down together with the intermediate presser 2, a light emitting unit 51 that is disposed on the inner bottom of the arm unit 103, and The optical sensor is provided with a light receiving portion 52. The light shielding plate 53 receives the light reception from the light emitting unit 51 when the intermediate presser 2 is raised toward the standby position and when the intermediate presser 2 reaches the standby position or a lower side before the standby position. In this embodiment, the position detection sensor 5 is positioned at the position where the intermediate presser 2 reaches the height of the standby position. Can be detected.

(Control system)
Next, the configuration of the control unit 6 of the sewing machine 1 will be described with reference to the block diagram of FIG.
As shown in FIG. 2, the control unit 6 is a main control unit including a CPU 61, a RAM 62 as a storage unit, a ROM 63, an input interface (input I / F) 65, and an output interface (output I / F) 64. (Control means) 60 is provided.
An operation panel 66 including various switches and a position detection sensor 5 are connected to the main controller 60 via an input interface 65, and the sewing machine motor 11, pulse motor 41, and alarm means (buzzer) 67 are connected via an output interface 64. Etc. are connected. Further, drive circuits 11 a and 41 a for driving each motor are interposed between the output interface 64, the sewing machine motor 11, and the pulse motor 41.

  The ROM 63 stores pattern data corresponding to each preset sewing shape (sewing pattern). The pattern data includes a plurality of necessary data among the cloth feed amount, the needle swing amount, the sewing length, the number of stitches, and the like. Also, other data can be arbitrarily changed. The ROM 63 stores a drive control program for controlling the drive of each drive mechanism provided in the sewing machine 1.

  The CPU 61 calculates stitch data including XY coordinates of the needle drop point based on the pattern data and the drive control program. Then, based on the stitch data, the driving of the sewing machine motor 41, the pulse motor 41, etc. is controlled via the drive circuits 11a, 41a by the generation of the position detection signal of the position detection sensor 5, and the intermediate press driving means 3, The height adjusting means 4 is driven. Although not described in detail, the CPU 61 also performs drive control of other components of the sewing machine such as thread trimming, confirmation of whether or not the components are operating normally, and the like.

  The RAM 62 temporarily stores the stitch data calculated by the CPU 61 based on the drive control program, the total cloth feed amount described later, and the like. Further, when a part of the pattern data is changed, the changed pattern data is also temporarily stored.

  Further, the control unit 6 has a function of adjusting the height of the bottom dead center position in the vertical operation of the intermediate presser 2 during the sewing operation. In other words, the control unit 6 includes the sewing pattern and pattern data stored in the ROM 63 and the RAM 62 as storage means, the preset height setting data of the intermediate presser 2, and the intermediate presser calculated by the CPU 61 based on the drive control program. According to the optimum bottom dead center height in the vertical movement of 2, the necessary number of pulse signals are sent to the pulse motor 41 to control the drive so that the bottom dead center height of the intermediate presser 2 is always the optimum height. I have.

  The control unit 6 has a function of controlling the intermediate presser 2 to move up to the standby position every time a series of sewing operations are completed. That is, when a series of sewing operations is completed in accordance with the sewing pattern data stored in the ROM 63 and RAM 62, the control unit 6 sends a pulse signal for raising the intermediate presser 2 to the pulse motor 41 so that the intermediate presser 2 is directed to the standby position. It has a function to control to raise.

  Moreover, the control part 6 raises the intermediate presser 2 at every end of a series of sewing operations, and when the position detection sensor 5 detects the detected part (light-shielding plate 53) during the upward movement, the control part 6 stands by based on the detected position. It has a function to specify the position. That is, the control unit 6 sends a pulse signal to the pulse motor 41 to raise the intermediate presser 2 every time a series of sewing operations are completed based on the sewing pattern data stored in the ROM 63 and RAM 62, and the position of When the CPU 61 confirms that the detection sensor 5 has detected the presence of the intermediate presser 2, the standby position is determined based on the number of pulses at that time, and the function of performing the control of waiting the intermediate presser 2 at the standby position is provided. . For example, when the position detection sensor 5 detects the presence of the intermediate presser 2 while the intermediate presser 2 is being lifted, the position of the pulse motor 41 or the intermediate presser 2 at that time is set as the standby position or detected. Control is performed such as determining a position that has risen several pulses from the position as a standby position.

  Further, the control unit 6 raises the intermediate presser 2 at the end of a series of sewing operations, and when the position detection sensor 5 detects the detected portion (light-shielding plate 53) while moving to the standby position, the control unit 6 returns to the origin based on the detection position. It has a function of performing correction processing. That is, the control unit 6 sends a pulse signal to the pulse motor 41 to raise the intermediate presser 2 every time a series of sewing operations are completed based on the sewing pattern data stored in the ROM 63 and RAM 62. As soon as the position detection sensor 5 detects the arrival of the intermediate presser 2 at the standby position during ascending, it has a function of performing control for newly determining the position of the origin based on the number of pulses of the pulse motor 41 at that time. For example, the function of performing control such as determining the position at the time point detected by the position detection sensor 5 as a new origin point, or determining the position raised by a predetermined number of pulses from the detected time point as the new origin point. It is what has.

  Further, when the intermediate presser 2 is moved upward to the standby position, the control unit 6 determines whether or not the position detection sensor 5 detects the arrival of the intermediate presser 2 at the standby position every time the pulse motor 41 rotates by one pulse. It has the function to perform control to confirm whether. That is, every time the pulse motor 41 rotates by one pulse, the CPU 61 repeats the operation of confirming whether or not the position detection sensor 5 has detected the arrival of the intermediate presser 2 and keeps the intermediate presser 2 until the detection is confirmed. The control to raise is performed.

  Further, the controller 6 does not detect that the intermediate presser 2 has been raised to the standby position by the position detection sensor 5 even after the pulse motor 41 has rotated by an amount corresponding to the predetermined allowable number of pulses. In this case, it has a function of controlling to perform error processing. That is, if the position detection sensor 5 does not detect the arrival of the intermediate presser 2 even if the pulse signal is sent to the pulse motor 41 by the number of pulse signals that the intermediate presser 2 can sufficiently reach the standby position, It has a function to perform control so as to sound an alarm.

Further, the control unit 6 may be controllable so that the above-described lifting operation of the intermediate presser 2 to the standby position or the accompanying origin correction processing operation of the pulse motor 41 is performed even when the sewing machine 1 is turned on. In this embodiment, the origin correction process is controlled not only at the end of a series of sewing operations but also when the sewing machine 1 is turned on.
In this embodiment, the error processing is controlled to sound an alarm when the arrival of the intermediate presser 2 is not detected. However, the present invention is not necessarily limited to this. For example, an error display is provided by providing display means. Or may be controlled to stop the sewing machine 1.
Further, it is desirable that the “allowable pulse number” is the number of rising pulses from the sewing position to the standby position or a value somewhat larger than that.

Next, the operation of the sewing machine 1 according to this embodiment will be described in detail.
In the present embodiment, the intermediate presser 2 is synchronized with the sewing needle with a smaller amplitude than the sewing needle in the region above the workpiece to be sewn placed on the sewing machine bed 101 by the intermediate presser driving means 3 described above during the sewing operation. Then moved up and down. That is, the sewing product is brought into contact with the sewing product prior to the sewing needle that sews the sewing product up and down, presses the sewing product downward until the sewing needle is pulled out of the sewing product, and the sewing needle is pulled out. After that, it rises with this sewing needle.

  At that time, according to the sewing pattern stored in advance in the ROM 63 and RAM 62 of the control unit 6, if the workpiece held by the outer presser (not shown) is moved in the horizontal direction by the outer presser drive mechanism (not shown), the desired sewing is performed. In order to form a pattern according to the pattern, a pulse signal is sent from the CPU 61 to the pulse motor 41 according to the change in the cloth thickness, and the bottom dead center position of the intermediate presser 2 that moves up and down together with the sewing needle is adjusted to an optimum height as needed. Is done.

  Further, in accordance with a series of sewing patterns stored in the storage means of the control unit 6, a pulse signal is sent from the control unit 6 to the pulse motor 41 in order to raise the intermediate presser 2 toward the standby position after the sewing operation is completed. Control is performed.

  Next, the control operation of the control unit 6 provided in the sewing machine 1 according to this embodiment will be described in detail with reference to the flowchart shown in FIG.

First, when the power of the sewing machine 1 is turned on (step S1), the sewing needle is raised to the upper position using the sensor provided in the sewing machine motor 11 (step S2).
Next, an origin correction process for the intermediate presser 2 is performed (step S3). That is, the CPU 61 performs control for driving the pulse motor 41 in the upward direction of the intermediate presser 2 until the position detection sensor 5 detects the presence of the intermediate presser 2 in the standby position.
Next, control is performed to move the outer presser holding the workpiece to the origin position in the horizontal direction (XY direction) (step S4).
Then, control is performed to move the outer presser whose origin is corrected in the horizontal direction to the sewing start position in accordance with the inputted sewing pattern data (step S5).
At the sewing start position, the outer presser foot is raised, and a state where the cloth which is the workpiece is set can be set (step S6).
When the cloth is set and the presser switch is turned on (step S7), the outer presser descends and the cloth is fixed, and the sewing is ready (step S8).
Next, when the start switch is pressed (step S9), the control unit 6 drives and controls each unit in accordance with sewing data stored or input in advance in the RAM 62 and ROM 63, thereby performing desired sewing (step S10).
Then, every time a series of sewing operations is completed (step S11), the sewing needle is controlled to stop at the upper position (step S12), and then the intermediate presser 2 is raised toward the standby position (step S13). At this time, the CPU 63 determines whether or not the presence of the intermediate presser 2 at the standby position is detected by the position detection sensor 5 every time the intermediate presser 2 is raised by one pulse, as in the case of the above-described steps S3 and S4. The drive is controlled so as to rise while checking.
When the presence of the intermediate presser 2 at the standby position is detected (that is, when the intermediate presser 2 is raised and reaches the standby position) (step S14; Yes), the intermediate presser 2 (that is, the pulse motor 41) After the origin correction processing is performed (step S17), control is performed so as to wait at a predetermined standby position. In the origin correction processing, for example, when the sensor position of the position detection sensor 5 is set to the 10th pulse below the origin, the RAM 62 indicates that the current pulse count value is −10th pulse at the time of sensor detection. The storing process is performed by the CPU 61. After the origin correction processing, the count value is incremented by 1 every time one pulse is detected by the pulse motor 41 during upward rotation, and 1 is decremented by each time one pulse is detected during downward rotation. In this way, even if the intermediate presser 2 is displaced in either the upper side or the lower side (that is, even if the pulse motor 41 is stepped out in any direction), the origin correction process is surely performed. It can be performed.
If the presence of the intermediate presser 2 at the standby position is not detected by the position detection sensor 5 (step S14; No), it is determined whether or not the allowable number of pulses stored in advance in the storage means has been exceeded (step S15). If the allowable number of pulses is not reached (step S15; No), the intermediate presser 2 is again raised by one pulse (step S13), and the same confirmation operation is repeated. If the allowable number of pulses has been exceeded (step S15; Yes), the CPU 61 checks again whether or not the presence of the intermediate presser 2 at the standby position is detected by the position detection sensor 5 (step S16). ). If the presence of the intermediate presser 2 is detected at the standby position (step S16; Yes), after performing the origin correction process for the intermediate presser 2 (step S17), the process proceeds to step S5. On the other hand, if not detected (step S16; No), the CPU 61 executes an error process for giving an alarm by the alarm means 67 (step S18).
Here, the “allowable number of pulses” is calculated and stored in advance in accordance with the distance from the state where the bottom dead center of the intermediate presser 2 is the lowest at the time of sewing to the position where it rises and reaches the standby position. The number of stored pulses. The “allowable pulse number” is preferably a value that sufficiently exceeds the number of pulses from the lowest position to the standby position during sewing, and an arbitrary value is set according to the desired cycle time in the sewing machine operation. Is desirable.

As described above, according to the sewing machine 1 according to the present embodiment, the bottom dead center height of the intermediate presser 2 is adjusted in real time in accordance with the change in the cloth thickness for each sewing pattern stored or input in advance during the sewing operation. Adjustments can be made. Thereby, desired sewing can be performed correctly.
Further, since the adjustment of the bottom dead center height in the vertical movement of the intermediate presser 2 during the sewing operation and the raising operation to the standby position after the completion of the sewing operation are enabled by one pulse motor 41, the intermediate presser can be driven. The actuator for adjusting the height position of 2 can be covered by one, and desired sewing can be performed while suppressing the cost.
Further, by performing control so that the intermediate presser 2 is raised and waits at the standby position every time a series of sewing operations is completed, the replacement or replacement work of the workpiece can be easily performed.
In addition, the control unit 6 performs the origin correction process of the pulse motor 41 for each series of sewing operations, so that the bottom dead center height in the vertical movement of the intermediate presser 2 is not changed at the next sewing, according to the sewing pattern. Accurate sewing can be performed.
Further, when the origin correction process of the pulse motor 41 is performed, control is performed so as to confirm whether or not the intermediate presser 2 has reached the standby position every time one pulse is raised. The origin correction process can be performed.
At that time, if the arrival of the intermediate presser 2 at the standby position is not detected even if the allowable number of pulses is exceeded, the operator can be notified of the abnormality of the sewing machine 1 by performing error processing, and the trouble remains. Sewing is not continued and the quality of sewing is not impaired.

Second Embodiment
Next, the second embodiment of the present invention will be described in detail. In addition, the description of the same structure as 1st Embodiment and the overlapping is attached | subjected and abbreviate | omitted. Since the sewing machine of the present embodiment is different from the sewing machine 1 of the first embodiment only in the processing to be executed, only the different processing will be described.

In the present embodiment, the control unit 6 that is a control means does not perform sensor detection confirmation for each pulse as in the first embodiment when performing the origin search. First, the intermediate presser 2 is defined by the pulse motor 41. The CPU 61 has a function of performing control to confirm whether or not the position detection sensor 5 has detected that the intermediate presser 2 has reached and reached the standby position after being raised by an amount corresponding to the number of pulses. Yes.
That is, as shown in the flowchart of FIG. 4, from step S1 to step S11, the same processing as that of the first embodiment described above is executed, and then the needle bar is first stopped at the upper position after each series of sewing operations. (Step S20), the intermediate presser 2 is raised by sending a prescribed number of pulse signals to the pulse motor 41 (Step S21), and then whether or not the position detection sensor 5 detects the arrival of the intermediate presser 2 is determined. The CPU 61 has a function of controlling so as to confirm (step S22).
In this way, the same effect as in the first embodiment can be obtained, and the lifting speed of the intermediate presser 2 can be increased without considering the time required for the confirmation operation of the CPU 61 until the number of pulses increases by the specified number of pulses. Therefore, the time required for the origin correction process of the pulse motor 41 can be greatly shortened. That is, the cycle time of the sewing machine operation can be greatly shortened.
If the arrival of the intermediate presser 2 at the standby position is not detected even after the specified number of pulses have been raised (step S22; No), then the intermediate presser is applied to the pulse motor 41 by one pulse as described above. 2 is sent (step S24), and the possibility of detecting the arrival of the position detection sensor 5 is confirmed again (step S22), and repeated until the arrival of the intermediate presser 2 at the standby position is detected. You may control to.
In this way, the origin correction process of the pulse motor 41 can be reliably performed, and the cycle time of the sewing machine operation can be shortened. Accordingly, there is no step-out in the pulse motor 41 at the next sewing. That is, there is no deviation between the height of the intermediate presser 2 recognized by the control unit 6 and the actual height of the intermediate presser 2, and desired sewing can be performed accurately.

It is the schematic which shows the intermediate presser drive mechanism of the sewing machine which concerns on 1st Embodiment. It is a control block diagram which shows the outline of the control part of the sewing machine which concerns on 1st Embodiment. It is a flowchart which shows the operation principle of the sewing machine which concerns on 1st Embodiment. It is a flowchart which shows the operation principle of the sewing machine which concerns on 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sewing machine 2 Intermediate presser 3 Intermediate presser drive means 31 Sewing machine motor 31a, 41a Drive circuit 41 Pulse motor 42 Adjustment screw 43 Adjustment member 44 Groove 45 Stopper 51 Position detection sensor (light emission part)
52 Position detection sensor (light receiving part)
53 Light-shielding plate 6 Control unit 61 CPU
62 RAM (storage means)
63 ROM (storage means)
64 output I / F
65 input I / F
66 Operation panel (various switches)
101 Bed section 102 Vertical trunk section 103 Arm section

Claims (4)

An intermediate presser that regulates the ascent of the sewing product as the needle rises by moving up and down in synchronization with the needle;
An intermediate presser driving means for driving the intermediate presser up and down in synchronization with the needle;
A height adjusting means capable of adjusting the height of the bottom dead center in the vertical movement of the intermediate presser;
Detecting means for detecting arrival when the intermediate presser is raised;
Control means capable of driving and controlling the height adjusting means,
The height adjusting means is configured such that both the height adjustment of the bottom dead center position of the intermediate presser during the sewing operation and the operation of raising the intermediate presser to the standby position can be driven by one pulse motor,
The control means raises the intermediate presser toward the standby position at the end of a series of sewing operations, and performs the origin correction processing of the pulse motor from the height of the intermediate presser at the time of detection by the detection means. Characteristic sewing machine.   2. The control unit according to claim 1, wherein when the intermediate presser is moved up to a standby position, the control unit performs control for confirming whether or not the detection unit has reached each time the pulse motor rotates by one pulse. Sewing machine.   The control means performs control for checking whether or not the intermediate presser has been raised to the standby position by the detection means after the intermediate presser has been raised by an amount corresponding to the prescribed number of pulses of the pulse motor. The sewing machine according to claim 1, wherein:   When the control means does not detect that the intermediate presser has been raised to the predetermined height position by the detection means even after the pulse motor has rotated by an amount corresponding to a predetermined allowable number of pulses, 4. The sewing machine according to claim 1, wherein control for performing error processing is performed.

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