JP5318444B2 - Buttonhole sewing machine - Google Patents

Abstract

The invention provides a buttonhole serging machine which matches with the sewed thickness, cuts the sewed object with proper cutting pressure, uses a cutter and a part opposite to the cutter to form a buttonhole on the sewed object. The buttonhole serging machine comprises: a pulse motor making the cutter or the part opposite to the cutter move back and forth between an origin position and cutting stopping position; a control unit controlling drive of the pulse motor; an encoder detecting actual rotation pulse of the pulse motor; a position deviation calculating unit calculating position deviation of drive pulse output by the control unit to the pulse motor and actual detected pulse of the pulse motor detected by the encoder; and a deviation storage unit storing permissible limit of the drive pulse and the actual detected pulse. The control unit corrects the drive pulse and then outputs the drive pulse to the pulse motor before the cutter or the part opposite to the cutter gets to thecutting stopping position under the condition that the deviation calculated by the deviation calculating unit is over the permissible limit so as to decrease position deviation.

Description

  The present invention relates to a buttonhole sewing machine provided with a knife mechanism that forms a buttonhole by a knife and a knife receiver.

For example, before or after forming the buttonhole stitching seam including the left and right side stitching portions on the sewing product, a knife for cutting the sewing product to form a button hole between the left and right side sewing portions; In a buttonhole sewing machine having a scalpel mechanism that has a scalpel mechanism that includes a scalpel holder that is disposed so as to be opposed to the scalpel and sandwiches the material to be sewn between the scalpel and causes the scalpel to cut the material to be sewn. One of the drive sources is converted into a pulse motor, and the conventional motor is mechanically driven by driving the pulse motor based on a preset number of correction pulses corresponding to the thickness and material of the cloth to be sewed. There has been known one that improves the efficiency of the setting operation of the movement amount of the knife receiver or the cloth cutting knife, which must be relied on for adjustment (see, for example, Patent Document 1).
JP 2002-200377 A

  However, in the conventional buttonhole sewing machine, although the number of pulses can be corrected, the pulse motor is driven only by a preset number of pulses, and the workpiece is cut by the knife and the knife receiver. In order to adapt to the sewing product that cuts the pressure, it was necessary to determine the number of correction pulses by repeating trial and error each time. Even if the thickness and material of the fabric are the same, if the size and shape of the button hole to be formed changes, it will be necessary to replace it with a knife that matches the size and shape of the corresponding button hole. It is necessary to set the number of correction pulses according to. Furthermore, even if the number of correction pulses is determined once, the knife and knife receiver always move with the same amount of movement, so they lack flexibility, for example, when the knife sharpness changes, the correction pulse again Had to change the number. That is, it cannot be said that the conventional buttonhole sewing machine can sufficiently cope with the above-mentioned various buttonhole forming conditions in the formation of the buttonhole, and the movement amount of the knife receiver or the cloth cutting knife is set. The work still requires a lot of time and has a problem that it contributes to a decrease in the sewing work.

  Accordingly, the present invention has been made to solve the above-described problems, and allows a workpiece to be sewn with an appropriate cutting pressure in accordance with the various button hole formation conditions described above without performing time-consuming setting work. It is an object of the present invention to provide a buttonhole sewing machine that can be cut.

The invention according to claim 1 is a knife (30) for cutting a sewing product, and a knife that is arranged opposite to the knife and that holds the sewing product between the knife and causes the knife to cut the sewing product. Before or after forming the buttonhole stitching seam including the left and right side stitching portions on the sewing product, and moving one of the knife and the knife receiver toward the other. In a buttonhole sewing machine that forms a buttonhole between the left and right side sewing parts of the sewing product,
A pulse motor (11) connected to one of the knife or the knife receiver and reciprocally moving the knife or the knife receiver between an origin position and a cutting end position;
Command signal means for outputting a command signal for moving the knife or the knife receiver;
Control means (7) for controlling the driving of the pulse motor so that the knife or the knife receiver reaches the movement position (lowering position) commanded by the command signal when the button hole is formed;
An encoder (13) as position detecting means for outputting a detection pulse corresponding to the actual movement position of the knife or the knife receiver;
Position deviation calculating means (S4) for calculating a position deviation between the movement position based on the command signal and the actual movement position;
A permissible limit storage means (72) for storing a permissible limit of the positional deviation;
When the position deviation calculated by the position deviation calculation means exceeds the allowable limit until the knife or the knife receiver reaches the cutting end position, the position deviation decreases the command signal. Correction means for correcting as follows ,
The permissible limit storage means stores a permissible limit for each of a plurality of sections obtained by dividing the knife or the knife receiver from the origin position to the cutting end position according to the distance from the origin position,
The instruction signal correcting means according to each allowable limit in the female or the knife receiver belongs interval, it characterized that you correct the command signal.

According to the first aspect of the present invention, the knife or the knife receiver is moved to the movement position commanded based on the command signal by the drive control of the pulse motor by the control means based on the command signal output from the command signal output means. To do. During this movement, the encoder detects the actual movement position of the knife or knife receiver via the detection pulse. The position deviation calculating means calculates a position deviation between the movement position commanded by the command signal and the actual movement position. Then, the command signal correction means, when the position deviation calculated by the position deviation calculation means exceeds the allowable limit stored in the deviation storage means until the knife or knife receiver reaches the cutting end position, The command signal is corrected so as to reduce the position deviation and output to the control means.
With the above configuration, in the vicinity of the moving position of the knife or the knife receiver where the position deviation becomes an allowable limit, if the position deviation exceeds the allowable limit, the command signal is corrected so that the position deviation decreases, and either the knife or the knife receiver is The movement of the knife and the knife receiver moves in the direction away from each other, the position deviation decreases with the movement and becomes within the allowable limit value, and either the knife or the knife receiver moves again toward the other. Repeated. As a result, in the vicinity of the moving position where the position deviation increases when the knife or the knife receiver comes into contact with the workpiece, inertial force directed to the other is within the range where the position deviation does not greatly exceed the allowable limit. Repeatedly transmitted, the cutting ability of the knife or the knife receiving cloth can be improved. In other words, in the present application, the cutting ability can be improved by repeated inertial force due to repeated contact and separation of the knife or the knife receiver. In addition, when the moving position where the repetitive contact / separation operation of the knife or knife receiver is performed is a position where the position deviation exceeds the allowable limit, a positive cutting force is required for either the knife or the knife receiver. Limited and repeated inertial force can be applied, and the cloth can be cut efficiently.
In addition, if the position deviation exceeds the allowable limit, the knife or knife receiver moves in the direction away from it, so it is possible to prevent the pulse motor and cloth cutting mechanism from being overloaded and damaged. And the life of the knife receiver can be improved.
Depending on the thickness and material of the material to be sewn, the size of the knife (female size), the shape of the knife, the button hole formation conditions such as the sharpness of the knife, the position where the position deviation exceeds the allowable limit and the force required for cutting In this application, the correction position is automatically determined at the moving position where the position deviation exceeds the allowable limit, and the repeated contact / separation operation of the knife or the knife receiver is performed when the position deviation falls below the allowable limit. Since the operation is automatically stopped, the number of contact / separation operations can be automatically changed according to the button hole forming conditions.
Therefore, cut the workpiece with appropriate cutting pressure according to the various formation conditions of the button holes such as the thickness and material of the workpiece, the size of the knife (female size), the shape of the knife, the sharpness of the knife, etc. Can do.

In addition , the movement range of the knife or knife receiver can be divided into a plurality of sections, and the command signal can be corrected according to the pre-stored allowable limit for each section. The correction amount of the command signal can be adjusted according to the thickness of the object.

The invention according to claim 2 is the buttonhole stitch sewing machine according to claim 1 ,
A movement amount storage means for storing a movement amount necessary to move the knife or the knife receiver from the origin position to the cutting end position;
A change amount calculating means for calculating a change amount of the position deviation during movement from the origin position of the knife or the knife receiver to the cloth cutting end position;
A reference value storage means for storing a reference value of a change amount of the position deviation, which is a reference for determining a moving position where the knife or the knife receiver comes into contact with the workpiece;
Thickness for calculating the thickness of the sewing product from the actual movement position of the knife or knife receiver detected by the encoder and the movement amount when it is determined that the change amount of the position deviation exceeds the reference value. Calculating means;
An allowable limit determining means for determining the allowable limit from the thickness of the sewing product calculated by the thickness calculating means;
It is characterized by providing.

According to the second aspect of the present invention, the thickness calculating means is configured so that the amount of change in the positional deviation calculated during the movement of the knife or the knife receiver from the origin position to the cloth cutting end position is stored in the reference value storage means. The actual movement position of the knife or the knife receiver detected by the encoder when it is determined that the stored reference value is exceeded, the movement amount stored in the movement amount storage means, and the actual movement position of the sewing product Calculate the thickness.
Then, the allowable limit determining means determines the allowable limit from the thickness of the workpiece calculated by the thickness calculating means.
Thereby, before the button hole is formed, the tolerance limit is determined based on the value obtained by actually moving the knife or the knife receiver, so that the accuracy of correction by the correction means can be improved.
The invention according to claim 3 is a scalpel (30) for cutting a sewing product, and a scalpel which is disposed to face the knife and sandwiches the sewing product between the knife and causes the knife to cut the sewing product. Before or after forming the buttonhole stitching seam including the left and right side stitching portions on the sewing product, and moving one of the knife and the knife receiver toward the other. In a buttonhole sewing machine that forms a buttonhole between the left and right side sewing parts of the sewing product,
A pulse motor (11) connected to one of the knife or the knife receiver and reciprocally moving the knife or the knife receiver between an origin position and a cutting end position;
Command signal means for outputting a command signal for moving the knife or the knife receiver;
Control means (7) for controlling the driving of the pulse motor so that the knife or the knife receiver reaches the movement position (lowering position) commanded by the command signal when the button hole is formed;
An encoder (13) as position detecting means for outputting a detection pulse corresponding to the actual movement position of the knife or the knife receiver;
Position deviation calculating means (S4) for calculating a position deviation between the movement position based on the command signal and the actual movement position;
A permissible limit storage means (72) for storing a permissible limit of the positional deviation;
When the position deviation calculated by the position deviation calculation means exceeds the allowable limit until the knife or the knife receiver reaches the cutting end position, the position deviation decreases the command signal. Correction means for correcting
A movement amount storage means for storing a movement amount necessary to move the knife or the knife receiver from the origin position to the cutting end position;
A change amount calculating means for calculating a change amount of the position deviation during movement from the origin position of the knife or the knife receiver to the cloth cutting end position;
A reference value storage means for storing a reference value of a change amount of the position deviation, which is a reference for determining a moving position where the knife or the knife receiver comes into contact with the workpiece;
Thickness for calculating the thickness of the sewing product from the actual movement position of the knife or knife receiver detected by the encoder and the movement amount when it is determined that the change amount of the position deviation exceeds the reference value. Calculating means;
A permissible limit determining means for determining the permissible limit based on the thickness of the sewing product calculated by the thickness calculating means;
It is characterized by providing.
According to the third aspect of the present invention, the knife or the knife receiver is moved to the movement position commanded based on the command signal by the drive control of the pulse motor by the control means based on the command signal output from the command signal output means. To do. During this movement, the encoder detects the actual movement position of the knife or knife receiver via the detection pulse. The position deviation calculating means calculates a position deviation between the movement position commanded by the command signal and the actual movement position. Then, the command signal correction means, when the position deviation calculated by the position deviation calculation means exceeds the allowable limit stored in the deviation storage means until the knife or knife receiver reaches the cutting end position, The command signal is corrected so as to reduce the position deviation and output to the control means.
With the above configuration, in the vicinity of the moving position of the knife or the knife receiver where the position deviation becomes an allowable limit, if the position deviation exceeds the allowable limit, the command signal is corrected so that the position deviation decreases, and either the knife or the knife receiver is The movement of the knife and the knife receiver moves in the direction away from each other, the position deviation decreases with the movement and becomes within the allowable limit value, and either the knife or the knife receiver moves again toward the other. Repeated. As a result, in the vicinity of the moving position where the position deviation increases when the knife or the knife receiver comes into contact with the workpiece, inertial force directed to the other is within the range where the position deviation does not greatly exceed the allowable limit. Repeatedly transmitted, the cutting ability of the knife or the knife receiving cloth can be improved. In other words, in the present application, the cutting ability can be improved by repeated inertial force due to repeated contact and separation of the knife or the knife receiver. In addition, when the moving position where the repetitive contact / separation operation of the knife or knife receiver is performed is a position where the position deviation exceeds the allowable limit, a positive cutting force is required for either the knife or the knife receiver. Limited and repeated inertial force can be applied, and the cloth can be cut efficiently.
In addition, if the position deviation exceeds the allowable limit, the knife or knife receiver moves in the direction away from it, so it is possible to prevent the pulse motor and cloth cutting mechanism from being overloaded and damaged. And the life of the knife receiver can be improved.
Depending on the thickness and material of the material to be sewn, the size of the knife (female size), the shape of the knife, the button hole formation conditions such as the sharpness of the knife, the position where the position deviation exceeds the allowable limit and the force required for cutting In this application, the correction position is automatically determined at the moving position where the position deviation exceeds the allowable limit, and the repeated contact / separation operation of the knife or the knife receiver is performed when the position deviation falls below the allowable limit. Since the operation is automatically stopped, the number of contact / separation operations can be automatically changed according to the button hole forming conditions.
Therefore, cut the workpiece with appropriate cutting pressure according to the various formation conditions of the button holes such as the thickness and material of the workpiece, the size of the knife (female size), the shape of the knife, the sharpness of the knife, etc. Can do.
Further, the thickness calculating means determines that the amount of change in the position deviation calculated during the movement of the knife or the knife receiver from the origin position to the cloth cutting end position exceeds the reference value stored in the reference value storage means. In this case, the thickness of the workpiece is calculated from the actual movement position of the knife or the knife receiver detected by the encoder, the movement amount stored in the movement amount storage means, and the actual movement position.
Then, the allowable limit determining means determines the allowable limit from the thickness of the workpiece calculated by the thickness calculating means.
Thereby, before the button hole is formed, the tolerance limit is determined based on the value obtained by actually moving the knife or the knife receiver, so that the accuracy of correction by the correction means can be improved.

The invention according to claim 4 is a button tension sewing machine according to claim 2 or 3, wherein a thread tension device for applying tension to the thread,
Thread tension control means for controlling the tension applied to the thread by controlling the driving of the thread tension device from the thickness of the sewing product calculated by the thickness calculating means;
It is characterized by providing.

  According to the invention described in claim 4, the yarn tension control means adjusts the tension applied to the yarn by controlling the driving of the yarn tension device from the thickness of the sewing product calculated by the thickness calculation means. The tension of the thread can be appropriately corrected according to the thickness of the sewing object.

The invention according to claim 5 is a buttonhole sewing machine according to any one of claims 2 to 4 , and a feed device that feeds the workpiece in the feed direction;
A feed timing control means for adjusting the feed timing of the sewing product by controlling the driving of the feeding device from the thickness of the sewing product calculated by the thickness calculation means;
It is characterized by providing.

  According to the fifth aspect of the invention, since the feed timing of the sewing product is adjusted by controlling the driving of the feeding device from the thickness of the sewing product calculated by the thickness calculating means, the thickness of the sewing product is adjusted. Accordingly, the feed timing of the sewing product can be appropriately corrected.

According to the first aspect of the present invention, the knife or the knife receiver is moved to the movement position commanded based on the command signal by the drive control of the pulse motor by the control means based on the command signal output from the command signal output means. To do. During this movement, the encoder detects the actual movement position of the knife or knife receiver via the detection pulse. The position deviation calculating means calculates a position deviation between the movement position commanded by the command signal and the actual movement position. Then, the command signal correction means, when the position deviation calculated by the position deviation calculation means exceeds the allowable limit stored in the deviation storage means until the knife or knife receiver reaches the cutting end position, The command signal is corrected so as to reduce the position deviation and output to the control means.
With the above configuration, in the vicinity of the moving position of the knife or the knife receiver where the position deviation becomes an allowable limit, if the position deviation exceeds the allowable limit, the command signal is corrected so that the position deviation decreases, and either the knife or the knife receiver is The movement of the knife and the knife receiver moves in the direction away from each other, the position deviation decreases with the movement and becomes within the allowable limit value, and either the knife or the knife receiver moves again toward the other. Repeated.
As a result, in the vicinity of the moving position where the position deviation increases when the knife or the knife receiver comes into contact with the workpiece, inertial force directed to the other is within the range where the position deviation does not greatly exceed the allowable limit. Repeatedly transmitted, the cutting ability of the knife or the knife receiving cloth can be improved. In other words, in the present application, the cutting ability can be improved by repeated inertial force due to repeated contact and separation of the knife or the knife receiver. In addition, when the moving position where the repetitive contact / separation operation of the knife or knife receiver is performed is a position where the position deviation exceeds the allowable limit, a positive cutting force is required for either the knife or the knife receiver. Limited and repeated inertial force can be applied, and the cloth can be cut efficiently.
In addition, if the position deviation exceeds the allowable limit, the knife or knife receiver moves in the direction away from it, so it is possible to prevent the pulse motor and cloth cutting mechanism from being overloaded and damaged. And the life of the knife receiver can be improved.
Depending on the thickness and material of the material to be sewn, the size of the knife (female size), the shape of the knife, the button hole formation conditions such as the sharpness of the knife, the position where the position deviation exceeds the allowable limit and the force required for cutting In this application, the correction position is automatically determined at the moving position where the position deviation exceeds the allowable limit, and the repeated contact / separation operation of the knife or the knife receiver is performed when the position deviation falls below the allowable limit. Since the operation is automatically stopped, the number of contact / separation operations can be automatically changed according to the button hole forming conditions.
Therefore, cut the workpiece with appropriate cutting pressure according to the various formation conditions of the button holes such as the thickness and material of the workpiece, the size of the knife (female size), the shape of the knife, the sharpness of the knife, etc. Can do.

In addition , the movement range of the knife or knife receiver can be divided into a plurality of sections, and the command signal can be corrected according to the pre-stored allowable limit for each section. The correction amount of the command signal can be adjusted according to the thickness of the object.

According to the second aspect of the present invention, the thickness calculating means is configured so that the amount of change in the positional deviation calculated during the movement of the knife or the knife receiver from the origin position to the cloth cutting end position is stored in the reference value storage means. The actual movement position of the knife or the knife receiver detected by the encoder when it is determined that the stored reference value is exceeded, the movement amount stored in the movement amount storage means, and the actual movement position of the sewing product Calculate the thickness.
Then, the allowable limit determining means determines the allowable limit from the thickness of the workpiece calculated by the thickness calculating means.
Thereby, before the button hole is formed, the tolerance limit is determined based on the value obtained by actually moving the knife or the knife receiver, so that the accuracy of correction by the correction means can be improved.
According to the third aspect of the present invention, the knife or the knife receiver is moved to the movement position commanded based on the command signal by the drive control of the pulse motor by the control means based on the command signal output from the command signal output means. To do. During this movement, the encoder detects the actual movement position of the knife or knife receiver via the detection pulse. The position deviation calculating means calculates a position deviation between the movement position commanded by the command signal and the actual movement position. Then, the command signal correction means, when the position deviation calculated by the position deviation calculation means exceeds the allowable limit stored in the deviation storage means until the knife or knife receiver reaches the cutting end position, The command signal is corrected so as to reduce the position deviation and output to the control means.
With the above configuration, in the vicinity of the moving position of the knife or the knife receiver where the position deviation becomes an allowable limit, if the position deviation exceeds the allowable limit, the command signal is corrected so that the position deviation decreases, and either the knife or the knife receiver is The movement of the knife and the knife receiver moves in the direction away from each other, the position deviation decreases with the movement and becomes within the allowable limit value, and either the knife or the knife receiver moves again toward the other. Repeated. As a result, in the vicinity of the moving position where the position deviation increases when the knife or the knife receiver comes into contact with the workpiece, inertial force directed to the other is within the range where the position deviation does not greatly exceed the allowable limit. Repeatedly transmitted, the cutting ability of the knife or the knife receiving cloth can be improved. In other words, in the present application, the cutting ability can be improved by repeated inertial force due to repeated contact and separation of the knife or the knife receiver. In addition, when the moving position where the repetitive contact / separation operation of the knife or knife receiver is performed is a position where the position deviation exceeds the allowable limit, a positive cutting force is required for either the knife or the knife receiver. Limited and repeated inertial force can be applied, and the cloth can be cut efficiently.
In addition, if the position deviation exceeds the allowable limit, the knife or knife receiver moves in the direction away from it, so it is possible to prevent the pulse motor and cloth cutting mechanism from being overloaded and damaged. And the life of the knife receiver can be improved.
Depending on the thickness and material of the material to be sewn, the size of the knife (female size), the shape of the knife, the button hole formation conditions such as the sharpness of the knife, the position where the position deviation exceeds the allowable limit and the force required for cutting In this application, the correction position is automatically determined at the moving position where the position deviation exceeds the allowable limit, and the repeated contact / separation operation of the knife or the knife receiver is performed when the position deviation falls below the allowable limit. Since the operation is automatically stopped, the number of contact / separation operations can be automatically changed according to the button hole forming conditions.
Therefore, cut the workpiece with appropriate cutting pressure according to the various formation conditions of the button holes such as the thickness and material of the workpiece, the size of the knife (female size), the shape of the knife, the sharpness of the knife, etc. Can do.
Further, the thickness calculating means determines that the amount of change in the position deviation calculated during the movement of the knife or the knife receiver from the origin position to the cloth cutting end position exceeds the reference value stored in the reference value storage means. In this case, the thickness of the workpiece is calculated from the actual movement position of the knife or the knife receiver detected by the encoder, the movement amount stored in the movement amount storage means, and the actual movement position.
Then, the allowable limit determining means determines the allowable limit from the thickness of the workpiece calculated by the thickness calculating means.
Thereby, before the button hole is formed, the tolerance limit is determined based on the value obtained by actually moving the knife or the knife receiver, so that the accuracy of correction by the correction means can be improved.

  According to the invention described in claim 4, the yarn tension control means adjusts the tension applied to the yarn by controlling the driving of the yarn tension device from the thickness of the sewing product calculated by the thickness calculation means. The tension of the thread can be appropriately corrected according to the thickness of the sewing object.

  According to the fifth aspect of the invention, since the feed timing of the sewing product is adjusted by controlling the driving of the feeding device from the thickness of the sewing product calculated by the thickness calculating means, the thickness of the sewing product is adjusted. Accordingly, the feed timing of the sewing product can be appropriately corrected.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The best mode of a buttonhole sewing machine according to the present invention will be described below in detail with reference to the drawings.
<Configuration of buttonhole sewing machine>
[Embodiment 1]
FIG. 1 is an explanatory diagram for explaining a schematic configuration of a buttonhole sewing machine (hereinafter simply referred to as “sewing machine”) 1 provided with a cloth cutting device 10 for a sewing machine according to the present embodiment.
The sewing machine 1 is a sewing machine that forms a button hole of a predetermined shape by automatic control and performs over stitching around the button hole. A bed part 2 and a bed part 2 on which a cloth as a sewing object is placed on the upper surface side. A pedestal 3 standing up from above, an arm 4 extending along the longitudinal direction from the pedestal 3 onto the bed 2, a feed base 5 for moving the workpiece in a horizontal plane, and a feed base 5 includes a cloth presser 6 for pressing the cloth on the upper surface, a cloth cutting device 10 for forming a button hole, a control device 7 (see FIG. 3) for controlling the operation of the sewing machine 1, and the like.

(Cloth cutting device)
The cloth cutting device 10 forms an eyelet buttonhole or a sleepy buttonhole when buttonhole sewing is performed.
As shown in FIGS. 1 and 2, the cloth cutting device 10 includes a cloth cutting means 20. The cloth cutting means 20 is disposed so as to face the knife 30 and the knife 30. A knife receiver 50 is provided which sandwiches the workpiece between them and causes the knife 30 to cut the workpiece. The cloth cutting means 20 is arranged so that the knife 30 faces upward with the knife receiver 50 facing down, and the knife 30 descends with respect to the knife receiver 50 to cut the workpiece.

The knife 30 has, on the lower surface thereof, a piglet knife part 30a that forms a piglet part and a straight knife part 30b that forms a straight part as blade parts. The knife 30 is movably fitted to the knife mounting base 31. The knife mounting base 31 is fixed by a screw 33 to a vertical shaft 32 that can be moved up and down by the pulse motor 11 (see FIG. 3).
The vertical shaft 32 is fitted to a metal 34 so as to be movable up and down, and is attached to the lower surface of the arm portion 4 with a screw 35 at the metal 34.
That is, as the pulse motor 11 is driven, the knife 30 reciprocates in the vertical direction between the origin position that is the top dead center and the cutting end position that is the bottom dead center.

  The female receiver 50 is fixed to a female base 52 fixed to the upper surface of the bed portion 2 by screws 51 with a female fixing plate 53 and screws 54. A key K is attached to the female base 52 with two screws 55, and the upper surface of the bed portion 2 can be moved in parallel with the depth direction in FIG. 2 (the left-right direction in FIG. 1).

(Control device)
As shown in FIG. 3, the control device 7 performs a calculation process related to the driving of the sewing machine 1 to control the driving source, data and parameters necessary for sewing and cloth cutting, and the CPU 71 controls the driving of the sewing machine 1. And a memory 72 that stores a program necessary for the operation and also serves as a work place for the CPU 71.

The control device 7 is connected to a pulse motor 11 that is connected to the knife 30 and reciprocates between the knife 30 and the cutting end position. The control device 7 is connected to the origin sensor 12 for detecting the origin position of the knife 30 described above, and the pulse motor 11 has an A phase having a phase difference of 90 degrees corresponding to the rotational position of the pulse motor 11. An encoder 13 that outputs two detection pulses consisting of a pulse and a B-phase pulse (the two are also called an AB-phase pulse) is connected, and the control device 7 is output from the encoder 13 based on the origin position. The lowered position as the actual movement position of the knife 30 can be detected in real time based on the phase relationship of the AB phase pulses and the number of each pulse. That is, the encoder 13 outputs a detection pulse corresponding to the actual movement position of the knife 30.
The pulse motor 11 is connected to the knife 30 of the cloth cutting device 10 via the vertical shaft 32 and serves as a drive source for the knife 30.
The control device 7 is connected to a solenoid (not shown) of a thread tension device 15 that applies tension to the yarn.
The control device 7 is connected to a feed motor (not shown) of a feed device 16 that feeds the cloth in the feed direction.

The memory 72 stores a command signal output program for outputting a command signal for commanding a lowered position for lowering the knife 30. That is, when the CPU 71 executes processing based on the command signal output program, the control device 7 functions as command means for outputting a command signal for commanding the knife 30 to move.
In the memory 72, a position deviation Pb between the lowered position (P1) as the moving position of the knife 30 commanded by the command signal and the actual detected position (P2) of the knife 30 detected by the encoder 13 is calculated. A position deviation calculation program is stored. That is, when the CPU 71 executes processing based on the position deviation calculation program, the control device 7 functions as position deviation calculation means.
The memory 72 stores a control program for controlling the driving of the pulse motor 11 so that the knife 30 reaches the movement position based on the command signal when the button hole is formed. That is, when the CPU 71 executes processing based on the control program, the control device 7 functions as control means.
In the memory 72, a command signal for correcting the command signal so that the position deviation Pb decreases until the knife 30 reaches the cutting end position when the position deviation Pb exceeds an allowable limit a0 (described later). A correction program is stored. That is, when the CPU 71 executes processing based on the command signal correction program, the control device 7 functions as correction means.

In the memory 72, the amount of change in the position deviation Pb during the descent from the origin position of the knife 30 to the cloth cutting end position is calculated, and stored in the memory 2 as a reference for determining the position where the knife 30 contacts the cloth. A thickness calculation program for realizing the function of calculating the thickness t of the fabric when it is determined that the reference value do (described later) has been exceeded is stored. That is, when the CPU 71 executes processing based on the thickness calculation program, the control device 7 functions as a change amount calculation unit and a thickness calculation unit.
The memory 72 stores an allowable limit determination program for determining the allowable limit a0 from the calculated fabric thickness t. That is, when the CPU 71 executes processing based on the allowable limit determination program, the control device 7 functions as an allowable limit determination unit.

The memory 72 stores a yarn tension control program for controlling the tension applied to the yarn by controlling the driving of the yarn tension device 15 from the cloth thickness t calculated by executing the thickness calculation program. . That is, when the CPU 71 executes processing based on the yarn tension control program, the control device 7 functions as a yarn tension control means.
The memory 72 stores a feed timing control program for adjusting the feed timing of the cloth by controlling the driving of the feed device 16 from the cloth thickness t calculated by the execution of the thickness calculation program by the CPU 71. . That is, when the CPU 71 executes processing based on the feed timing control program, the control device 7 functions as a feed timing control means.

The memory 72 stores an allowable limit a0 between the movement position P1 of the knife 30 commanded by the command signal and the actual movement position P2 of the knife 30. That is, the memory 72 functions as an allowable limit storage unit.
Specifically, the actual operation of the pulse motor 11 is delayed with respect to the command signal output from the control device 7 to the pulse motor 11. Therefore, the command signal output to the control means at any time after the start of the pulse motor 11 when the knife 30 is located at the origin position until the knife 30 reaches the cutting end position. To what extent the positional deviation Pb between the movement position (hereinafter also simply referred to as the command movement position) P1 and the actual movement position (hereinafter also simply referred to as the actual movement position) P2 due to the detection pulse detected from the encoder may deviate. The allowable limit a0 is a threshold value indicating whether it is allowed. Therefore, when the deviation Pb between the command movement position P1 and the actual movement position P2 exceeds the allowable limit a0, the command signal is corrected by executing the command signal correction program by the CPU 71 in order to eliminate this deviation.
The memory 72 stores a movement amount (hereinafter also referred to as a total movement amount) b0 necessary for moving the knife 30 from the origin position to the cutting end position. That is, the memory 72 functions as a movement amount storage unit.
The memory 72 stores a thickness detection deviation d0 for determining that the knife 30 is in contact with the cloth. That is, the memory 72 functions as a thickness detection deviation storage unit.

Next, the cloth cutting operation controlled by the CPU 71 will be described.
<Cloth cutting process>
As shown in FIG. 4, when cutting the cloth by the cloth cutting device 10, the CPU 71 reads the allowable limit a0 and the total movement amount b0 stored in the memory 72 (step S1).
Next, as a command signal for moving the knife 30, the CPU 71 rotates the pulse motor 11 by a unit angle so that the knife 30 is lowered by a predetermined unit lowering amount (unit moving amount) with respect to the pulse motor 11. (Knife down command pulse) is output.
The unit angle can be arbitrarily determined, but is preferably at least the minimum angle determined by the resolution of the encoder 31. Here, the CPU 71 detects the actual lowering position of the knife 30 with a resolution that is four times the AB-phase pulse output from the encoder 71, and the CPU 71 is the same as the minimum angle determined by the resolution of the encoder 71. It is assumed that drive pulses are output so that the pulse motor 11 rotates at a unit angle.
Further, the allowable limit a0, the total movement amount b0, the thickness detection deviation d0, etc. stored in the memory 72 are also set in units of the above-described unit lowering amount so as to correspond to the detection pulse output from the encoder 31. It shall be.
Next, the CPU 71 adds 1 to a command position counter P1 provided in the CPU 71 in order to count the lowered position of the knife 30 commanded by the drive pulse (step S2).
Next, the CPU 71 reads the detection pulse (AB phase signal) output from the encoder 13 and updates the value of the lowering position counter P2 provided in the CPU 71 in order to count the actual lowering position of the knife 30 ( Step S3).
Next, the CPU 71 calculates a position deviation (Pb = P1-P2) from the difference between the command position counter P1 and the lowered position counter P2 by executing a position deviation calculation program, and the calculated position deviation is stored in the memory 72. It is determined whether or not it is larger than the stored allowable limit a0 (step S4).

In step S4, when the CPU 71 determines that the calculated position deviation Pb exceeds the allowable limit a0 (step S4: YES), the CPU 71 lowers the actual lowering position of the cloth cutting knife 30 detected from the encoder 13. The position counter P2 is compared with the total movement amount b0 stored in the memory 72, and it is determined whether or not the knife 30 has reached the cutting end position (step S5).
On the other hand, when the CPU 71 determines in step S4 that the calculated position deviation Pb does not exceed the allowable limit a0 (step S4: NO), the CPU 71 performs the process of step S2 again to the pulse motor 11. On the other hand, a command to further lower the knife 30 by one unit pulse is issued.

  In step S5, when the CPU 71 determines that the knife 30 has not reached the cutting end position (step S5: NO), the CPU 71 corrects the command signal so as to decrease the position deviation Pb. (Step S6). Specifically, as shown in FIG. 5, when the knife 30 comes into contact with the cloth C on the knife receiver 50 and a cutting resistance higher than a predetermined value is applied to the knife 30, the drive pulse output to the pulse motor 11 is applied. When the pulse motor 11 does not move and a delay occurs in the descent of the knife 30, and the position deviation further increases and exceeds the allowable limit a0, the CPU 71 temporarily reverses the pulse motor 11 by a unit angle. A drive pulse (female elevation command pulse) is output to the pulse motor 11 so that 30 is increased by a unit increase amount corresponding to the reverse rotation angle of the pulse motor 11. Therefore, the knife 30 is raised by the unit rising amount, and the drive command pulse is corrected so as to approach the detection pulse. As a result, the difference between the command position counter P1 and the lowered position counter P2, that is, the command of the knife 30 is commanded. The position deviation Pb between the lowered position and the actual lowered position can be reduced. After the process of step S6, the CPU 71 performs the process of step S3 again, and updates the value of the descending position counter P2 corresponding to the actual descending position of the knife 30 based on the detection pulse output from the encoder 13.

  Next, the process proceeds to step S4. As described above, here, the knife 30 is raised by one unit pulse by the process of step S6, and the minute position deviation Pb is reduced, so the process of step S4 is performed. Then, a negative determination is made, the process of step S2 is executed again, 1 is added to the command position counter P1, and the knife 30 is lowered by the unit angle of the pulse motor 11 by the command. By controlling the CPU 71 to return to step S2 again from step S2 to step S6, the knife 30 comes into contact with and disengages from the cloth C so that once the knife 30 is subjected to a cutting resistance exceeding the allowable limit, the knife 30 rises once and descends again. Operate. Therefore, by the contact / separation operation of the series of scalpels 30, the scalpel 30 is repeatedly lowered so as to repeatedly strike the cloth C. The repeated contact / separation operation of the knife 30 is repeated until the position deviation Pb becomes smaller than the allowable limit a0, so that the knife 30 is gradually lowered even in the case of a thick cloth that cannot be cut by a single lowering operation of the knife 30. And the cutting ability of the cloth cutting mechanism 10 can be improved. Further, as soon as the position deviation Pb exceeds the allowable limit a0, the knife 30 rises and the load on each member constituting the cloth cutting means 20 such as the knife 30 and the knife receiver 50 is reduced. It is possible to extend the life of the members constituting the cloth cutting device 10.

On the other hand, when the CPU 71 determines in step S5 that the knife 30 has reached the cutting end position (step S5: YES), the CPU 71 outputs to the pulse motor 11 the knife 30 raised to the origin position (step S5). S7). Specifically, as shown in FIG. 6, when the lowering position counter P <b> 2 indicating the actual lowering position of the knife 30 and the total movement amount b <b> 0 are equal, the lower end of the knife 30 penetrates the cloth C and the knife receiver 50. It is in the position which contacts the upper end of. In this case, the knife 30 moves up to return to the origin position.
Then, when the knife 30 reaches the origin position, the CPU 71 stops outputting the drive pulse to the pulse motor 11 (step S8), and this process is terminated.

<Determination of acceptable limits>
Here, a method for determining the allowable limit a0 used in the cloth cutting process will be described.
As shown in FIG. 7, when determining the allowable limit, first, the CPU 71 reads the reference value d0 and the total movement amount b0 stored in the memory 72 (step S31). The reference value d0 is a reference value for determining that the knife 30 is in contact with the cloth, and the change amount of the position deviation Pb calculated during the movement of the knife 30 from the origin position to the cloth cutting end position. Is the value compared to
Next, the CPU 71 reads the detection pulse output from the encoder 13 and updates the value of the descending position counter P2 (step S32). Then, a deviation between the command position counter P1 and the actual descending position counter P2 detected from the encoder 13 is calculated, and this deviation is temporarily stored in the memory 72 as a reference position deviation Pa as shown in FIG. (Step S33). In the first step S33, since the pulse motor 11 is not driven, the reference deviation pa = 0.

The CPU 71 outputs a drive pulse to the pulse motor 11 so that the knife 30 is positioned downward by the unit downward amount, and adds 1 to the downward position counter P2 (step S34). Next, the detection pulse from the encoder 13 is read, and the descending position counter P2 indicating the actual position of the knife 30 is updated (step S35).
Next, the CPU 71 calculates a position deviation Pb between the command position counter P1 and the descending position counter P2 at this time (step S36).
Next, the CPU 71 calculates the difference between the reference deviation Pa and the position deviation Pb, that is, the change amount of the position deviation Pb while the knife 30 is descending, and determines whether the calculated change amount exceeds the reference value d0. (Step S37).

In step S37, when it is determined that the calculated change amount of the position deviation exceeds the reference value d0 (step S37: YES), the CPU 71 determines that the knife 30 is in contact with the cloth, and at this time The cloth thickness t is calculated by subtracting the value of the descending position counter P2 corresponding to the actual movement position of the knife 30 from the total movement amount b0 (step S38) (see FIG. 8).
Next, the CPU 71 adjusts the yarn tension by the yarn tension device 15 from the fabric thickness t, and adjusts the feed timing of the fabric by the feed device 16 from the fabric thickness t (steps S39 and S40).
Next, the CPU 71 derives and determines an allowable limit a0 corresponding to the thickness t from the fabric thickness t (step S41).

Here, as illustrated in FIG. 9, the memory 72 stores a table in which the cloth thickness t, the allowable limit a0, and the cloth cutting pressure exerted by the knife 30 are associated with each other. In this table, in the case of a thin cloth having a small cloth thickness t, the knife 30 does not have a large resistance, so the cutting pressure is small and the allowable limit a0 serving as a reference for correcting the drive pulse is also small.
Next, after determining the allowable limit a0, the CPU 71 performs the cloth cutting process shown in FIG. 4 (step S42).

<Effect>
Thus, according to the buttonhole sewing machine 1, the knife 30 moves up and down by the drive control of the pulse motor 11 by the control device 7. During this vertical movement, the encoder 13 detects the actual movement position of the pulse motor 11. The control device 7 includes a command position counter P1 corresponding to the movement position commanded by the drive pulse output to the pulse motor 11, and a lowering position counter P2 corresponding to the actual movement position of the pulse motor 11 detected by the encoder 13. The positional deviation Pb is calculated. Then, when the calculated position deviation Pb exceeds the allowable limit a0 stored in the memory 72, the control device 7 reduces the position deviation Pb until the knife 30 reaches the cutting end position. The drive pulse is corrected and output to the pulse motor 11.

As a result, in the vicinity of the lowering position of the knife 30 where the position deviation becomes an allowable limit, the position deviation Pb is corrected so as to decrease when the position deviation exceeds the allowable limit a0, and a drive pulse for the pulse motor 11 is output. The contact / separation operation of the knife 30 is repeated in which the knife 30 rises once, and the position deviation Pb decreases with the rise, falls within the allowable limit value, and the knife 30 is lowered again.
As a result, in the vicinity of the descent position of the knife 30 where the knife 30 comes into contact with the cloth C and the position deviation Pb increases, the inertia toward the knife receiver 50 in a range where the position deviation Pb does not greatly exceed the allowable limit a0 with respect to the knife 30. The force is transmitted repeatedly, and the cutting ability of the knife 30 cloth can be improved.

In other words, in the present application, the cutting ability can be improved by repeated inertial force due to repeated contact and separation operations of the knife 30. Further, since the descending position where the repetitive contact / separation operation of the knife 30 is performed is in the vicinity of the position where the position deviation Pb is equal to or greater than the allowable limit a0, it is limited to the case where a positive cutting force is required for the knife 30. Thus, repeated inertial force can be applied, and the cloth can be cut efficiently.
Further, if the position deviation Pb exceeds the allowable limit a0, the knife 30 moves in the upward direction, so that it is possible to prevent the pulse motor 11 and the cloth cutting means 20 from being overloaded and damaged. The life of the knife 30 and the knife receiver 50 can be improved.

The knife 30 in which a positional deviation Pb exceeding the allowable limit a0 occurs depending on the button hole formation conditions such as the thickness and material of the cloth C, the size of the knife 30 (female size), the shape of the knife 30, and the sharpness of the knife 30. However, in this application, the descent position of the knife 30 whose drive pulse is corrected is automatically determined so that the position deviation Pb is a descent position that exceeds the allowable limit a0. Since the contact / separation operation of the knife 30 is automatically stopped when the position deviation Pb falls below the allowable limit a0, the number of contact / separation operations can be automatically changed according to the button hole formation conditions.
Therefore, the material to be sewn can be applied with an appropriate cutting pressure in accordance with various formation conditions of button holes such as the thickness and material of the material to be sewn, the size of the knife 30 (female size), the shape of the knife 30 and the sharpness of the knife 30. Can be cut.

Further, when determining the allowable limit, when it is determined that the change amount (Pa−Pb) of the position deviation exceeds the reference value d0 stored in the memory 72, the total movement amount of the knife 30 stored in the memory 72 is determined. The thickness t of the cloth C is calculated from the deviation between b0 and the lowered position counter P2 corresponding to the actual lowered position of the knife 30.
Then, the control device 7 determines the allowable limit a0 from the calculated cloth thickness t.
Thereby, before the button hole is formed, the allowable limit a0 is determined based on the value obtained by actually moving the knife 30, so that the accuracy of the drive pulse correction by the control device 7 can be improved. .

Further, the control device 7 controls the drive of the yarn tension device 15 from the calculated fabric thickness t to adjust the tension applied to the yarn, so that the yarn tension is appropriately adjusted according to the fabric thickness t. It can be corrected.
Further, the control device 7 controls the driving of the feeding device 16 from the calculated fabric thickness t to adjust the fabric feeding timing, so that the fabric feeding timing is appropriately corrected according to the fabric thickness t. can do.

[Embodiment 2]
Next, Embodiment 2 will be described. In the second embodiment, a plurality of allowable limits are stored in the memory 72, and control related to the cloth cutting process is performed by using the allowable limit corresponding to the position of the knife. Therefore, the same components as those of the first embodiment are denoted by the same reference numerals and description thereof is omitted.
Specifically, as shown in FIG. 10, the memory 72 has a plurality of sections divided from the origin position of the knife 30 to the cutting end position according to the distance from the origin position, in other words, the knife from the origin position. Permissible limits a1, a2, a3 (where a1 ≦ a2 ≦ a3) for each of a plurality of sections divided according to 30 distances (falling amounts) b0, b1, b2, b3 (where b1>b2> b3) Is set. That is, in the second embodiment, a section from the origin position to a height corresponding to the descending amount b3, a section from a height corresponding to the descending amount b3 to a height corresponding to the descending amount b2, and a height corresponding to the descending amount b2. Is divided into four sections, a section from the height corresponding to the descent amount b1 and a section from the height corresponding to the descent amount b1 to the cutting end position, and from the height corresponding to b3 from the origin position to the cutting end position. Permissible limits a3, a2 and a1 are set for each of the sections up to. Here, in the section from the origin position to the height corresponding to b3, it is assumed that the cloth thicker than that is not handled, and only the process of lowering the knife 30 is executed, and the cloth cutting process is not performed. .
The control device 7 corrects the drive pulse so that the positional deviation Pb is decreased and outputs it to the pulse motor 11 when the allowable limit a1, a2, a3 corresponding to the section exceeds the section in which the knife 30 belongs. .

<Cloth cutting process>
As shown in FIG. 11, when cutting the cloth by the cloth cutting device 10, the CPU 71 reads the allowable limits a1, a2, a3 and the descending amounts b0, b1, b2, b3 stored in the memory 72 ( Step S11). Each allowable limit a1, a2, a3 and each descent amount b0, b1, b2, b3 are set to values corresponding to the number of pulses output from the encoder 71. Next, the CPU 71 outputs a drive pulse for a unit angle to the pulse motor 11 so as to lower the knife 30 by a unit lowering amount, and adds 1 to the command position counter P1 (step S12).
Next, the CPU 71 updates the descending position counter P2 based on the detection signal from the encoder 13 (step S13).
Next, the CPU 71 determines whether or not the descending position of the knife 30 has reached a height corresponding to the descending amount b3 from the origin position based on the value of the descending position counter P2 (step S14).

In step S14, when the CPU 71 determines that the descent position of the knife 30 has reached a height corresponding to the descent amount b3 from the origin position (step S14: YES), the CPU 71 determines that the descent position of the knife 30 is the origin. It is determined whether or not the height corresponding to the descending amount b2 from the position has been reached (step S15).
On the other hand, when the CPU 71 determines in step S14 that the descent position of the knife 30 has not reached the height corresponding to the descent amount b3 from the origin position (step S14: NO), the CPU 71 again executes step S12. Process.

  In step S15, when the CPU 71 determines that the descent position of the knife 30 has not reached the height corresponding to the descent amount b2 from the origin position (step S15: NO), the CPU 71 executes the position deviation calculation program. Thus, the deviation deviation Pb is calculated, and it is determined whether or not the calculated position deviation Pb is larger than the allowable limit a3 stored in the memory 72 (step S16).

In step S16, when the CPU 71 determines that the calculated position deviation Pb is larger than the allowable limit a3 (step S16: YES), the CPU 71 corrects the drive pulse so that the position deviation Pb is reduced, and the pulse motor 11 is corrected. (Step S17). Specifically, a drive pulse that temporarily reverses the pulse motor 11 is output so as to raise the knife 30 by a unit increase amount. Thereby, the position deviation Pb can be reduced. After the process of step S17, the CPU 71 performs the process of step S13 again.
On the other hand, when the CPU 71 determines in step S16 that the calculated position deviation Pb is equal to or less than the allowable limit a3 (step S16: NO), the CPU 71 returns to the process of step S12 again.

  In step S15, when the CPU 71 determines that the descent position of the knife 30 has reached a height corresponding to the descent amount b2 from the origin position (step S15: YES), the CPU 71 determines that the descent position of the knife 30 is the origin. It is determined whether or not the height corresponding to the descending amount b1 from the position has been reached (step S18).

  In step S18, when the CPU 71 determines that the descent position of the knife 30 has not reached a height corresponding to the descent amount b1 from the origin position (step S18: NO), the CPU 71 executes a position deviation calculation program. Thus, the position deviation Pb is calculated, and it is determined whether or not the calculated position deviation Pb is larger than the allowable limit a2 stored in the memory 72 (step S19).

In step S19, when the CPU 71 determines that the calculated deviation is larger than the allowable limit a2 (step S19: YES), the CPU 71 corrects the drive pulse so that the position deviation Pb decreases, and outputs it to the pulse motor 11. (Step S20). Specifically, a drive pulse that temporarily reverses the pulse motor 11 by a unit angle so as to raise the knife 30 is output. Thereby, the position deviation Pb can be reduced. After the process of step S20, the CPU 71 performs the process of step S13 again.
On the other hand, when the CPU 71 determines in step S19 that the calculated position deviation PB is equal to or less than the allowable limit a2 (step S19: NO), the CPU 71 returns to the process of step S12 again.

  In step S18, if the CPU 71 determines that the descent position of the knife 30 has reached a height corresponding to the descent amount b1 from the origin position (step S18: YES), the CPU 71 determines that the descent position of the knife 30 is the origin. It is determined whether or not the height (in other words, the cutting end position) corresponding to the descent amount b0 (total movement amount) from the position has been reached (step S21).

  In step S21, when the CPU 71 determines that the descent position of the knife 30 has not reached the height corresponding to the descent amount b0 from the origin position (step S21: NO), the CPU 71 executes the position deviation calculation program. Thus, the position deviation Pb is calculated, and it is determined whether or not the calculated position deviation Pb is larger than the allowable limit a1 stored in the memory 72 (step S23).

In step S22, when the CPU 71 determines that the calculated position deviation Pb is larger than the allowable limit a1 (step S22: YES), the CPU 71 corrects the drive pulse so that the position deviation Pb decreases, and performs the pulse motor 11 correction. (Step S23). Specifically, a drive pulse that temporarily reverses the pulse motor 11 by a unit angle is output so as to raise the knife 30 by a small amount on the unit. Thereby, the position deviation Pb can be reduced. After the process of step S23, the CPU 71 performs the process of step S13 again.
On the other hand, when the CPU 71 determines in step S22 that the calculated deviation is equal to or less than the allowable limit a1 (step S22: NO), the CPU 71 returns to the process of step S12 again.

In step S21, when the CPU 71 determines that the descent position of the knife 30 has reached the height corresponding to the descent amount b0 from the origin position (step S21: YES), the CPU 71 causes the knife 30 to return to the origin. A drive pulse is output to the pulse motor 11 so as to rise to the position (step S24).
Then, when the knife 30 reaches the origin position, the CPU 71 stops outputting the drive pulse to the pulse motor 11 (step S25), and this process is terminated.

<Effect>
According to the sewing machine in the second embodiment, the movement range of the knife 30 is divided into a plurality of sections, and the position deviation Pb is driven to decrease when the position deviation Pb exceeds the allowable limit set and stored for each section. Since the pulse can be corrected, the correction amount of the driving pulse can be adjusted according to the thickness of the cloth.
That is, for example, as shown in FIG. 12, by associating the allowable limit with the cloth thickness t and the cutting pressure, the CPU 71 allows the position deviation Pb to be within the range where the cloth thickness t is 2 mm <t ≦ 3 mm. Is determined to exceed 8 pulses, the drive of the pulse motor 11 is controlled so as to cut at a cutting pressure of 800 kgf. When the cloth is cut and the cloth thickness t is in the range of 1 mm <t ≦ 2 mm and the position deviation Pb exceeds 5 pulses, the pulse motor 11 is driven so as to cut with a cutting pressure of 500 kgf. To control. Further, when the cloth is cut and the thickness t of the cloth is in the range of t ≦ 1 mm and the position deviation Pb exceeds 3 pulses, the CPU 71 causes the pulse motor 11 to cut with a cutting pressure of 300 kgf. Control the drive.
As a result, if the thickness of the cloth to be cut is large, it is cut with a large cutting pressure, and the driving pulse of the pulse motor is corrected so that the cutting pressure decreases as the cloth thickness decreases. And the impact of the knife 30 and the knife receiver 50 can be weakened to prevent the knife 30 from being lost.

<Others>
The present invention is not limited to the above embodiment. In the above embodiment, the upper knife is moved toward the lower knife receiver, but the arrangement of the knife and the knife receiver may be reversed, and the knife receiver is fixed by fixing the knife. You may make it move.
Further, the relationship data between the allowable limit and the cloth thickness as shown in FIG. 9 and FIG. 12 may be stored in a memory as a table, or these correlation equations are defined and the correlation equations are used. You may make it calculate.

FIG. 3 is a front view of the buttonhole stitching sewing machine according to the first embodiment. The front view of the cloth cutting device in case the knife in Embodiment 1 exists in an origin position. FIG. 2 is a block diagram illustrating a configuration around a control device according to the first embodiment. 3 is a flowchart illustrating a cloth cutting process according to the first embodiment. The front view of the cloth cutting device in the middle of the knife in Embodiment 1 cutting the cloth. The front view of the cloth cutting device in case the knife in Embodiment 1 exists in a cutting end position. 5 is a flowchart of processing for determining an allowable limit in the first embodiment. The front view of the cloth cutting device when determining the tolerance limit in Embodiment 1. FIG. The figure which shows the example of the table which matched the allowable limit in Embodiment 1, the thickness of the cloth, and the cutting pressure. The front view of the cloth cutting device in case the knife in Embodiment 2 exists in an origin position. 9 is a flowchart illustrating a cloth cutting process according to the second embodiment. The figure which shows the example of the table which matched the allowable limit in Embodiment 2, the thickness of the cloth, and the cutting pressure.

Explanation of symbols

1 buttonhole sewing machine 7 control device (control means, command signal output means, position deviation calculation means, thickness calculation means, allowable limit determination means, change amount calculation means, thread tension control means, feed timing control means, correction means )
72 memory (position deviation storage means, movement amount storage means, reference value storage means)
DESCRIPTION OF SYMBOLS 10 Cloth cutting device 11 Pulse motor 13 Encoder 15 Thread tension device 16 Feed device 30 Knife 50 Knife receptacle C Cloth (to be sewn)

Claims (5)

A right and left side stitching portion, comprising: a knife for cutting the workpiece, and a knife receiver that is disposed opposite to the knife and sandwiches the workpiece between the knife and cuts the workpiece by the knife. Before or after forming the buttonhole over stitching seam on the sewing product, one of the knife or the female receptacle is moved toward the other side and the buttonhole is formed between the left and right side sewing parts of the sewing product. In the buttonhole sewing machine that forms
A pulse motor connected to one of the knife or the knife receiver and reciprocally moving the knife or the knife receiver between an origin position and a cutting end position;
Command signal output means for outputting a command signal for moving the knife or the knife receiver;
Control means for controlling the driving of the pulse motor so that the knife or the knife receiver reaches the movement position commanded by the command signal when the button hole is formed;
An encoder that outputs a detection pulse corresponding to the actual movement position of the knife or the knife receiver;
Position deviation calculating means for calculating a position deviation between the movement position commanded by the command signal and the actual movement position;
A tolerance limit storage means for storing a tolerance limit of the positional deviation;
When the position deviation calculated by the position deviation calculation means exceeds the allowable limit until the knife or the knife receiver reaches the cutting end position, the position deviation decreases the command signal. Correction means for correcting
Equipped with a,
The permissible limit storage means stores a permissible limit for each of a plurality of sections obtained by dividing the knife or the knife receiver from the origin position to the cutting end position according to the distance from the origin position,
The instruction signal correcting means, the female or according to each allowable limit in the knife receiver belongs interval, button sewing machine characterized that you correct the command signal. A movement amount storage means for storing a movement amount necessary to move the knife or the knife receiver from the origin position to the cutting end position;
A change amount calculating means for calculating a change amount of the position deviation during movement from the origin position of the knife or the knife receiver to the cloth cutting end position;
A reference value storage means for storing a reference value of a change amount of the position deviation, which is a reference for determining a moving position where the knife or the knife receiver comes into contact with the workpiece;
Thickness for calculating the thickness of the sewing product from the actual movement position of the knife or knife receiver detected by the encoder and the movement amount when it is determined that the change amount of the position deviation exceeds the reference value. Calculating means;
A permissible limit determining means for determining the permissible limit based on the thickness of the sewing product calculated by the thickness calculating means;
The buttonhole sewing machine according to claim 1, further comprising: A right and left side stitching portion, comprising: a knife for cutting the workpiece, and a knife receiver that is disposed opposite to the knife and sandwiches the workpiece between the knife and cuts the workpiece by the knife. Before or after forming the buttonhole over stitching seam on the sewing product, one of the knife or the female receptacle is moved toward the other side and the buttonhole is formed between the left and right side sewing parts of the sewing product. In the buttonhole sewing machine that forms
  A pulse motor connected to one of the knife or the knife receiver and reciprocally moving the knife or the knife receiver between an origin position and a cutting end position;
  Command signal output means for outputting a command signal for moving the knife or the knife receiver;
  Control means for controlling the driving of the pulse motor so that the knife or the knife receiver reaches the movement position commanded by the command signal when the button hole is formed;
  An encoder that outputs a detection pulse corresponding to the actual movement position of the knife or the knife receiver;
  Position deviation calculating means for calculating a position deviation between the movement position commanded by the command signal and the actual movement position;
  A tolerance limit storage means for storing a tolerance limit of the positional deviation;
  When the position deviation calculated by the position deviation calculation means exceeds the allowable limit until the knife or the knife receiver reaches the cutting end position, the position deviation decreases the command signal. Correction means for correcting
  A movement amount storage means for storing a movement amount necessary to move the knife or the knife receiver from the origin position to the cutting end position;
  A change amount calculating means for calculating a change amount of the position deviation during movement from the origin position of the knife or the knife receiver to the cloth cutting end position;
  A reference value storage means for storing a reference value of a change amount of the position deviation, which is a reference for determining a moving position where the knife or the knife receiver comes into contact with the workpiece;
Thickness for calculating the thickness of the sewing product from the actual movement position of the knife or knife receiver detected by the encoder and the movement amount when it is determined that the change amount of the position deviation exceeds the reference value. Calculating means;
  A permissible limit determining means for determining the permissible limit based on the thickness of the sewing product calculated by the thickness calculating means;
  A buttonhole sewing machine characterized by comprising: A yarn tensioning device for applying tension to the yarn;
Thread tension control means for controlling the tension applied to the thread by controlling the driving of the thread tension device from the thickness of the sewing product calculated by the thickness calculating means;
The buttonhole overlock sewing machine according to claim 2 or 3, characterized in that A feeding device for feeding the workpiece in the feeding direction;
A feed timing control means for adjusting the feed timing of the sewing product by controlling the driving of the feeding device from the thickness of the sewing product calculated by the thickness calculation means;
The buttonhole sewing machine according to any one of claims 2 to 4 , further comprising:

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