JP5555470B2 - sewing machine - Google Patents

Description

  The present invention relates to a sewing machine including a thread trimming device.

A conventional thread trimming device of a sewing machine includes a thread trimming cam (original mechanism of a cam mechanism) that is rotated by a sewing machine motor, and a roller that can be switched between engagement and disengagement with respect to a cam groove of the thread trimming cam ( A follower of the cam mechanism), a moving knife that performs a thread trimming operation in conjunction with the roller, and a thread trimming solenoid that engages the roller with the groove cam.
In the conventional sewing machine, the roller is engaged with the thread trimmer cam by the thread trimmer solenoid while maintaining the sewing motor at a predetermined speed with the last needle of sewing, and the thread trimmer is utilized by making one rotation of the last needle of the machine motor. Thread cutting is performed by applying a cutting operation from the cam to the moving knife (see, for example, Patent Document 1).

JP 2007-181609 A

By the way, in the case of a mechanism for operating a moving knife using a thread trimming cam as in the conventional sewing machine as described above, a section in which a roller can engage with the cam groove (referred to as an engagement section) is formed. Furthermore, an operation section for applying a cutting operation to the moving knife is formed on the downstream side. When the roller is engaged with the thread trimming cam, the thread trimming solenoid is driven at a main shaft angle at which the cam groove engagement section is positioned with respect to the roller.
In contrast, the thread trimming solenoid has a time lag from when it receives a drive command due to an external factor such as a load until it actually starts to operate, and the roller may be damped in the cam groove. The roller does not engage properly with the cam groove until it has settled. For this reason, the time required for the sum of the time lag and the braking time of the damping is required from the start to the completion of the roller engaging operation.
The rotational speed of the sewing machine motor during cutting of the sewing thread is set to a low speed for the stability of the cutting operation, set to a high speed for speeding up the work, or adjusted as necessary. ing.

In other words, an almost constant time is always required from the start to the completion of the roller engagement operation. On the other hand, the rotational speed of the sewing machine motor at the time of thread cutting is arbitrarily set in the range from low to high. As a result, the following problems occurred.
In other words, if the rotation speed of the sewing machine when cutting the sewing thread is set to a high speed, the thread trimming cam will also rotate at a high speed, so it will operate from the cam groove engagement section until the roller engagement operation is completed. There was a case where the transition to the section occurred, and the roller could not be engaged due to poor engagement.
Also, when sewing thread is cut, the hook presser called “picker” that presses against the bobbin in the hook from the outside of the hook to prevent the bobbin from spinning freely and secures the remaining length of the thread is interlocked with the roller by the thread trimming solenoid. Sometimes. In that case, if the rotation speed of the sewing machine when the sewing thread is cut is set to a low speed, the hook presser is abutted toward the bobbin before the sewing needle is retracted sufficiently upward with respect to the hook. In some cases, there was interference (contact) with the sewing needle. As a result, the hook presser may not function or the hook presser or the sewing needle may be destroyed.

  An object of the present invention is to further prevent cutting failure while suppressing a decrease in the efficiency of sewing work.

The invention according to claim 1 is a sewing machine motor that is a driving source for the vertical movement of a needle bar that holds a sewing needle, a thread cutting device that performs thread cutting using the power of the sewing machine motor, and the thread cutting device. A control means for controlling a sewing motor, a position detector for detecting an angle of a spindle that is rotationally driven by the sewing motor, and a speed setting means for setting the rotational speed of the sewing motor when the thread is cut. The trimming device includes a thread trimming cam that rotates by the sewing motor, a cam follower that performs a driven operation according to a cam groove of the thread trimming cam, and a motion that performs a thread cutting operation in conjunction with the cam follower. A knife, a thread trimmer solenoid that switches the cam follower from a non-coupled state to a coupled state with respect to the thread trimmer cam, and a thread trimmer solenoid that projects into the bobbin inside the shuttle in conjunction with the cam follower body. A hook presser that stops the rotation of the sewing machine, and the control means switches to the connected state by the thread trimming solenoid while driving the sewing machine motor at a rotational speed determined by the speed setting means. In a sewing machine that performs thread trimming control, the first thread trimming control that performs thread trimming after temporarily stopping the sewing machine motor and the second that performs thread trimming without temporarily stopping the sewing motor. The control means can set the lower stop angle and the thread trimming set rotation speed when the sewing machine motor is stopped in the first thread trimming control. communicating according to the driving start of the thread cutting solenoid to determine the waiting time until restarting the drive of the sewing machine motor, wherein the second thread cutting control of the cam follower member by the thread cutting solenoid In order to complete the switching operation to the state at a constant spindle angle, the spindle angle that is the appropriate operation start timing of the thread trimming solenoid is determined according to the rotational speed determined by the speed setting means, and the spindle angle in you and performs operation start control of the thread cutting solenoid.

  The invention according to claim 2 has the same configuration as that of the invention according to claim 1, and the control means completes the operation of switching the cam follower to the connected state by the thread trimming solenoid. Is a predetermined section between the main shaft angle at which the hook presser does not interfere with the sewing needle and the main shaft angle at which the cam follower cannot be switched to the connected state with respect to the thread trimming cam. It is characterized by being set.

  According to the first aspect of the present invention, even when the rotational speed of the sewing machine motor at the time of cutting control is arbitrarily determined, the main shaft angle at which the engagement operation of the cam follower is completed by the thread trimming solenoid can be made constant. In addition, since the drive start timing of the thread trimming solenoid is controlled, depending on the setting of the rotation speed of the sewing machine motor during cutting control, the hook presser and the sewing needle may interfere with each other, and the cam follower may not be able to engage with the cam groove. Thus, it is possible to avoid a situation in which a cutting failure occurs, and to prevent a cutting failure while suppressing a decrease in the efficiency of the sewing work.

  According to the second aspect of the present invention, the constant spindle angle at which the control means completes the switching operation of the cam follower to the connected state is the same as the spindle angle at which the hook presser does not cause the sewing needle to interfere with the thread trimmer cam. The cam follower body is set to a predetermined interval in the middle until the main shaft angle cannot be switched to the connected state, so that the hook presser and the sewing needle interfere with each other and the cam follower body engages with the cam groove. The switching operation of the cam follower to the connected state can be completed at a main shaft angle away from any main shaft angle at which a defect occurs. Accordingly, it is possible to more effectively prevent both interference between the hook presser and the sewing needle and poor engagement of the cam follower with the cam groove.

1 is a block diagram illustrating an overall configuration of a sewing machine that is an embodiment of the invention. It is the perspective view which looked at the sewing machine from the lower part in the state where the bottom plate was removed. It is the bottom view which looked at the thread trimming device from the lower part. It is sectional drawing along the VV line in FIG. It is an enlarged bottom view which shows the surrounding structure of a knife drive arm. It is a bottom view of a knife position adjustment body. It is a flowchart of sewing control. It is a diagram showing the change of the height (vertical axis) of the needle bar with respect to the main shaft angle (horizontal axis). It is explanatory drawing which shows the table for specifying suitable delay time by using the lower stop angle (theta) 1 and the thread trimming setting rotation speed v1 as a parameter. It is a flowchart which shows 1st cutting | disconnection control. It is explanatory drawing which shows the table for specifying the timing (spindle shaft angle) which starts the drive of the appropriate thread trimming solenoid by using the thread trimming set rotational speed v2 as a parameter. It is a flowchart which shows 2nd cutting control. It is explanatory drawing which shows the table which defined appropriate thread trimming setting rotation speed V1-V12 with respect to each value of the lower stop angle (theta) 1. It is a flowchart of the other example of 1st cutting | disconnection control.

(Outline of sewing machine)
A sewing machine 10 according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the overall configuration of the sewing machine 10, and FIG. 2 is a perspective view of the sewing machine 10 as viewed from below with the bottom plate removed.
The sewing machine 10 includes a needle up / down movement mechanism (not shown) that moves the sewing needle up and down, a hook mechanism (not shown) that captures the upper thread passed through the sewing needle and entangles the lower thread to form a seam, A cloth feed mechanism 20 that appears and disappears from an opening formed in the needle plate and feeds a sewing product in a predetermined cloth feed direction, a thread trimmer 30 that cuts an upper thread and a lower thread, and a movement of the thread trimmer 30 A thread trimming drive mechanism 50 that imparts a cutting operation to the knife 31; a control device 100 that serves as a control means that controls the operation of each of the above components; And.
In the following description, in a state where the sewing machine 10 is installed on the horizontal plane, the horizontal direction that coincides with the cloth feeding direction is the X-axis direction, the horizontal direction that is orthogonal to the X-axis direction is the Y-axis direction, and the vertical direction. The vertical direction is referred to as the Z-axis direction. Also, in one direction in the Z-axis direction, the upper side is “up”, the lower side is “down”, the direction in which the operator is positioned with respect to the sewing machine in one direction in the X-axis direction is “rear”, and the opposite side is “ As viewed from the operator side in one direction in the Y-axis direction, the left side is referred to as “left” and the right side is referred to as “right”.
In this embodiment, the thread trimming device 30 of the sewing machine 10 and the thread trimming drive mechanism 50 constitute a “thread trimming device” according to the present invention.

(Needle vertical movement mechanism)
The needle up-and-down movement mechanism is supported on the surface side of the sewing machine arm portion (not shown) in the sewing machine frame so as to be movable up and down and holds the sewing needle at the lower end, and a drive source for the vertical movement of the needle bar The sewing machine motor 1, the main shaft that is rotationally driven by the sewing motor 1, and a crank mechanism that converts the rotational driving of the main shaft into vertical movement and transmits it to the needle bar are the same as well-known ones.

(Hook mechanism)
The hook mechanism is a hook mechanism using a so-called full-rotation hook. The hook mechanism rotates the unillustrated full-rotation hook inside the sewing machine bed 2 and below the needle plate, and the full-rotation outer hook. The hook shaft 11 is provided and is similar to a well-known one. The shuttle shaft 11 is supported inside the sewing machine bed portion 2 so as to be rotatable along the Y-axis direction. The shuttle shaft 11 is given a rotational force from the sewing machine motor 1 so as to rotate at a double speed of the above-described main shaft (also referred to as an upper shaft).
The shuttle shaft 11 rotates in conjunction with the upper shaft, and forms a seam in cooperation with the sewing needle. The shuttle shaft 11 is disposed along the Y-axis direction (also referred to as the vertical feed shaft direction).

(Cloth feed mechanism)
The cloth feed mechanism 20 includes a feed base 21 having sawtooth-like feed teeth (not shown) protruding from the opening of a needle plate on the upper surface thereof, a vertical feed shaft 22 that is rotationally driven by the sewing machine motor 1, and a sewing machine motor. 1 is connected to the eccentric shaft of the eccentric cam 24, and the other end is the rear end of the feed base 21. And a horizontal feed arm 26 that is fixedly supported by the horizontal feed shaft 23 and that swings the swing end connected to the feed base 21 in the front-rear direction. The vertical feed shaft 22 is connected via a belt (not shown) so that when the main shaft makes one revolution, the vertical feed shaft 22 also makes one revolution with the same cycle as the main shaft (also referred to as the upper shaft).

The vertical feed shaft 22 is disposed rearward (operator side) of the hook shaft 11 inside the sewing machine bed portion 2 and is supported rotatably in a state along the Y-axis direction. The vertical feed shaft 22 is fixedly equipped with a toothed driven pulley (not shown) so that torque is applied via a toothed timing belt from the main pulley provided on the main shaft of the needle vertical movement mechanism. It has become. That is, the vertical feed shaft 22 is configured to be rotationally driven by the sewing machine motor 1 via the main shaft, and the transmission ratio is set so as to rotate at the same speed as the main shaft.
When the vertical feed shaft 22 performs full rotation, the vertical feed rod 25 transmits only the vertical movement component of the circular motion performed by the eccentric shaft of the eccentric cam 24 to the feed base 21, and the feed base 21 moves the sewing needle up and down. It moves up and down at the same cycle as the movement.
Incidentally, the hook shaft 11 described above is configured to be rotated by the vertical feed shaft 22 through the speed increasing gear train, and the rotary motion is imparted at a double speed of the vertical feed shaft 22. ing.

The horizontal feed shaft 23 is disposed closer to the front than the shuttle shaft 11 inside the sewing machine bed portion 2 and is rotatably supported in a state along the Y-axis direction. The above-described vertical feed shaft 22 is provided with an eccentric rod that holds an eccentric cam (not shown) fixedly mounted on the vertical feed shaft 22, and the horizontal feed shaft 23 is fixedly equipped with a driven arm (not shown). Yes. Then, the end of the eccentric rod that is not on the eccentric cam side and the swinging end of the driven arm are connected, so that a reciprocating rotation operation is imparted from the vertical feed shaft 22 to the horizontal feed shaft 23. ing. That is, the horizontal feed shaft 23 is configured to be reciprocally rotated by the sewing machine motor 1 via the vertical feed shaft 22 and the main shaft, and has the same reciprocating rotation cycle as the rotation cycle of the vertical feed shaft 22. The transmission ratio is set as follows.
As a result, the feed table 21 is provided with reciprocating vertical movement and reciprocating back-and-forth movement in the same cycle, and by appropriately adjusting these phases, the feed table 21 performs an elliptical motion along the cloth feeding direction. It is like that. The feed dog of the feed base 21 protrudes upward from the opening of the needle plate in the upper section of the elliptical motion, and the elliptical rotation direction of the feed base 21 so that the moving direction coincides with the cloth feed direction. Is adjusted, and it is possible to feed a needle-plate-like workpiece in a predetermined feeding direction.

(Thread trimming device)
FIG. 3 is a bottom view of the thread trimming device 30 as viewed from below.
As shown in the figure, the thread trimmer 30 rotates the main body frame 32, the fixed knife 33 fixedly supported on the main body frame 32, the moving knife 31 rotatably supported on the main body frame 32, and the moving knife 31. And an operating arm 34.
The moving knife 31 is pivotally supported by the step screw 35 so as to be rotatable with respect to the main body frame 32. The two-dot chain line shows the standby position, and the solid line shows the last retracted position in the reciprocating rotation. . During sewing, the moving knife 31 is in the position of the two-dot chain line and is separated from the illustrated needle drop position S. At the time of cutting, the thread to be cut is distributed by retreating to the solid line position, and the thread is advanced again to the position of the two-dot chain line, and the sewing thread is cut in cooperation with the fixed knife 33.
The fixed knife 33 is provided with a blade part 33a, and when the moving knife 31 moves backward, the thread sandwiched between the blade part 31a of the moving knife 31 and the blade part 33a of the fixed knife 33 is cut. It has become.

The operating arm 34 is pivotally supported with respect to the main body frame 32 by a step screw 36 at an intermediate position in the longitudinal direction, and one end thereof is connected to a second link body 61 of a thread trimming drive mechanism 50 described later. Has been. Further, a groove-shaped notch 34 a into which an engaging convex portion 31 b provided on the upper surface of the moving knife 31 is fitted is formed at the other end of the operating arm 34, and as the operating arm 34 rotates. Thus, the moving knife 31 can be rotated. In addition, since the notch 34a is formed in a groove shape in this way, the engaging convex part 31b can move inside the notch 34a, and the difference in the turning radius between the operating arm 34 and the moving knife 31 is possible. Can be tolerated.
With this structure, in the thread trimming device 30, the second link body 61 of the thread trimming drive mechanism 50 moves forward and backward in the right direction and the left direction, so that the end on the notch 34a side of the operating arm 34 is leftward. The thread cutting operation can be performed by rotating rightward and then rotating the moving knife 31 in the same direction.

(Thread trimming drive mechanism)
4 is a cross-sectional view taken along line VV in FIG.
As shown in FIGS. 2 and 4, the thread trimming drive mechanism 50 is configured as a cam follower that can be engaged with a thread trimming cam 51 fixedly mounted on the vertical feed shaft 22 and a cam groove 51 a of the thread trimming cam 51. , A knife driving arm 53 that holds the roller 52 by the input portion 53a and reciprocally rotates to transmit the cutting operation to the moving knife 31, a support shaft 54 that supports the knife driving arm 53, and a knife driving arm. 53, a clutch member 55 for applying a switching operation from a retracted position where the roller 52 is not fitted into the cam groove 51a to a fitting position where the roller 52 is fitted to the cam groove 51a, and a thread trimming solenoid as an actuator serving as a drive source for the switching operation of the clutch member 56, a first stopper 57 that engages with the knife drive arm 53 when the roller 52 is in the retracted position and prohibits the forward movement of the moving knife 31, and an output portion 53b of the knife drive arm 53 at one end. But The connected first link body 58 (also referred to as a link body), a female position adjusting body 59 as a female position adjusting means connected to the other end of the first link body 58, and a female position adjusting body 59 A second stopper 60 (also referred to as a stopper) that can be adjusted to stop the knife driving arm 53 at one end of the moving knife 31 at the movement start side in the rotation range, and a knife position adjusting body 59. A second link body 61 (also referred to as a moving knife drive link) that connects the operating arm 34 of the thread trimming device 30 is provided.

The thread trimming cam 51 is formed in a substantially disk shape when viewed from the Y-axis direction, and is fixedly supported by the vertical feed shaft 22 located at the center thereof, and is formed on the right end surface perpendicular to the vertical feed shaft 22. A cam groove 51a having an axial direction as a depth direction is formed.
The cam groove 51a has a non-displacement section that is a fixed distance from the vertical feed shaft 22 that is the center of rotation and a displacement section that returns to the same distance as the non-displacement section after gradually approaching the vertical feed shaft 22 that is the center of rotation. Only the displacement section is connected to the endless ring. When the vertical feed shaft 22 has an axial angle at which the roller 52 faces the non-displacement section, the roller 53 enters or leaves the cam groove 51a. Further, when the roller 52 that has entered the cam groove 51 a is present in the displacement section, a displacement in the substantially Z-axis direction is input from the cam groove 51 a and the displacement is transmitted to the knife drive arm 53. In addition, the displacement section is formed in a range of 285 ° to 45 ° with a spindle angle described later, and the section of 45 ° to 285 ° is a non-displacement section.

FIG. 5 is an enlarged bottom view showing the configuration around the knife drive arm 53.
As shown in FIGS. 2, 3, and 4, the knife driving arm 53 includes a cylindrical base portion 53 c that is fixed to the support shaft 54, and an input portion 53 a that extends outward in the rotational radial direction from the base portion 53 c. An output portion 53b extending in a direction different from the input portion 53a from the base portion 53c in the rotational radius direction, and an input portion 53a and an output portion 53b in the rotational radial direction from the base portion 53c. And a position restricting projection 53d extending in a different direction. That is, in a state where the knife driving arm 53 is supported by the support shaft 54, the position restricting projection 53d extends substantially downward, the input portion 53a extends generally forward in the X-axis direction, and the output portion. 53b extends substantially upward.
Further, the input portion 53a, the base portion 53c, and the position regulating projection 53d of the knife drive arm 53 are positioned below all of the vertical feed shaft 22, the horizontal feed shaft 23, and the shuttle shaft 11, and the output portion 53b is fed up and down. All of the shaft 22, the horizontal feed shaft 23, and the shuttle shaft 11 are positioned above.
Since the inside of the sewing machine bed portion 2 has three vertical feed shafts 22, horizontal feed shafts 23, and shuttle shafts 11 arranged in parallel, these shafts 22, 23, and 11 are used as a boundary to the lower area. Although divided into the upper area, the knife drive arm 53 extends from the lower side to the upper side of the shafts 22, 23, 11 as described above. A configuration (clutch member 55, thread trimming solenoid 56, first stopper 57, etc.) used to engage with or release the thread trimming cam 51 is disposed in the lower area, and the knife 31 moves from the knife driving arm 53. It is possible to arrange all the configurations (the first link body 58, the female position adjustment body 59, the second link body 61, etc.) that transmit the operation until the upper area.

Furthermore, since the knife drive arm 53 includes an input portion 53a and an output portion 53b that are rotating ends extending in two directions with respect to the support shaft 54, the knife drive arm 53 has a bell crank structure. With this structure, when a rotation operation is input from the roller 52 provided in the input unit 53a according to the cam groove 51a, the output unit 53b also performs a rotation operation, and the arc generated by the rotation of the output unit 53b. The first link body 58 connected so as to be along the tangential direction of the movement trajectory can be given an advancing / retreating movement operation along the longitudinal direction (roughly the X-axis direction).
Further, the knife driving arm 53 is formed with a protrusion 53e along the Y-axis direction (also referred to as the vertical feed axis direction). The protrusion 53e is provided with a through hole, and a later-described support shaft 54 is inserted into the through hole. Then, the knife driving arm 53 is fixed to the support shaft 54 by the screw 70.
Instead of this, it is easily conceivable to provide two E-rings or two thrust collars on the support shaft 54 to support both ends of the knife drive arm 53 in the Y-axis direction. It is also conceivable that a step portion is provided on one end side of the support shaft 54 and the female drive arm 53 is attached, and then the other end side is locked with an E-ring or the like. As described above, the knife driving arm 53 may be rotatably supported, and the knife driving arm 53 may be moved together in the Y axis direction as the support shaft 54 moves in the Y axis direction.

Both ends of the support shaft 54 are sewing machines so that the sewing bed portion 2 can advance and retract along the Y-axis direction (also referred to as the vertical feed axis direction) and rotate around the Y-axis. Supported by the frame. The support shaft 54 only needs to be able to advance and retract along the Y-axis direction by a collar, a bearing, or the like provided on the sewing machine frame.
Accordingly, the knife driving arm 53 can perform the forward / backward movement and the rotation operation similar to the support shaft 54. Further, the support shaft 54 is provided with a flange portion 54a, and the support shaft 54 and the female drive arm 53 are always pressed rightward by a pressing spring 62 via the flange portion 54a.
On the other hand, the first stopper 57 has a concave portion 57a formed on the right side of the position regulating projection 53d, and is adjacent to the front side of the concave portion 57a and maintains the state where the roller 52 is engaged with the cam groove 51a. For this purpose, an engagement maintaining projection 57b that is convex to the left is formed.
As described above, since the knife drive arm 53 is always pressed rightward by the pressing spring 62, the state where the position restricting protrusion 53d is fitted in the recess 57a that is recessed rightward is maintained. It has become. When the position regulating projection 53d is pressed to the left against the pressing spring 62 by the thread trimming solenoid 56 and the clutch member 55, it can be detached from the recess 57a, and further, the input of the female drive arm 53 The roller 52 held by the arm 53a is fitted into the cam groove 51a, and the knife driving arm 53 is rotated by the displacement section of the cam groove 51a so that the position restricting projection 53d moves forward. Then, the engagement maintaining projection 57b is in contact with the position restricting projection 53d immediately to the right (the state indicated by the two-dot chain line in FIG. 5). The roller 52 does not move to the right, and the roller 52 is maintained so as not to be detached from the cam groove 51a.

  As described above, the thread trimming solenoid 56 and the clutch member 55 are disposed in the lower area. The clutch member 55 is pivotally supported by the sewing machine bed portion 2 so as to be rotatable about the Z axis at an intermediate portion in the longitudinal direction, and one of the rotating end portions is rotated counterclockwise when viewed from the bottom. The contact portion 55a is configured to contact the position restricting projection 53d of the knife driving arm 53 and release the holding state by the first stopper 57. Further, adjacent to the contact portion 55a, there is a yarn tension releasing portion 55b connected to the releasing wire 12 for releasing the yarn tension applying state by an unillustrated upper yarn tensioning device. The yarn tension releasing portion 55b is operated so as to release the yarn tension at the same time when the contact portion 55a rotates in a direction to release the holding state of the position regulating projection 53d.

A plunger of a thread trimming solenoid 56 is connected to the vicinity of the other rotation end of the clutch member 55 so that the rotation of the clutch member 55 is biased. When the thread trimming solenoid 56 is not driven, the plunger is in a protruding state, and when it is driven, the plunger is in a retracted state to urge the clutch member 55 to rotate counterclockwise as viewed from the bottom.
Further, the other rotating end of the clutch member 55 is connected to a connecting link member 63 for pulling the hook thread presser 13 for preventing rotation of the bobbin accommodated in the inner hook of the hook mechanism into the rotation blocking state. ing. Thus, when the thread trimming solenoid 56 rotates the clutch member 55 counterclockwise as viewed from the bottom, the hook thread presser 13 is simultaneously rotated to prevent the bobbin from rotating, and the bobbin thread is cut during thread trimming. Can be prevented from being unsuccessfully cut out from the bobbin.

  FIG. 6 is a bottom view of the female position adjustment body 59. The female position adjusting body 59 includes first and second rotating pieces 64 and 65 (also referred to as a plurality of L-shaped rotating links) overlapped with each other, and these are integrally connected by a connecting screw 66. At the same time, the two rotating pieces 64 and 65 are pivotally supported around the Z axis by one step screw 67 at the same time. The first turning piece 64 includes a turning end portion that extends generally to the left in the Y-axis direction, and the turning end portion is connected to the end portion of the first link body 58. The second rotating piece 65 includes a rotating end portion that extends generally forward in the X-axis direction, and the rotating end portion is connected to the end portion of the second link body 61. With this structure, the female position adjustment body 59 has a bell crank structure. That is, when a rotation operation is applied to the first rotation piece 64 from the advance / retreat operation of the first link body 58 along the X-axis direction, the step screw 67 (also referred to as a support shaft) is used as a support shaft. The second rotating piece 65 is also rotated in the same direction, and can be given an advancing / retreating operation to the second link body 61 generally along the Y-axis direction.

  Further, the first rotating piece 64 (also referred to as a first L-shaped rotating link) is biased counterclockwise by a tension spring 68 as viewed from the bottom. A second stopper 60 is provided at the counterclockwise rotation destination of one rotation piece 64, and the state where the first rotation piece 64 is pressed against the second stopper 60 is maintained. It is like that. The rotation angle at which the first rotation piece 64 is held by the second stopper 60 is a position at which the roller 52 can enter the non-displacement section of the cam groove 51a via the first link body 58. Thus, the rotation angle for maintaining the rotation angle of the knife drive arm 53. The second stopper 60 is composed of a headless screw (head screw) 60a and a nut 60b for fixing the position of the screw. By screwing the screw 60a and fastening with the nut 60b, The stop angle of one rotating piece 64 can be adjusted. That is, the second stopper 60 and the tension spring 68 function as an initial position adjusting mechanism for the roller 52 (cam follower) that can adjust the initial position of the roller 52.

Further, the second rotating piece 65 (also referred to as a second L-shaped rotating link) is connected to the first rotating piece 64 by a connecting screw 66 through an elongated hole 65a. Is loosened, the elongated hole 65a allows the first turning piece 64 and the second turning piece 65 around the stepped screw 67 to be mutually rotated. When the initial position adjustment of the roller 52 is performed by the above-described second stopper 60 in the fastening state of the connection screw 66, the entire knife position adjusting body 59 is rotated and the standby position of the moving knife 31 is changed. In such a case, the standby position of the moving knife 31 is adjusted while appropriately adjusting the initial position of the roller 52 by loosening the connecting screw 66 and adjusting only the second rotating piece 65. It becomes possible to adjust to an appropriate position.
As described above, in the present embodiment, the first rotating piece 64 and the second rotating piece 65 are used. Instead of this, it is easy to think of using a single rotating piece to connect a link body 58 to one end side and a moving knife drive link 61 (described later) to the other end side to provide the same function. It is done.
Moreover, although the stopper 60 was comprised so that it might contact | abut to the 1st rotation piece 64, it can also be considered easy to comprise so that it may contact | abut the link body 58 mentioned later.

The link body 58 connects the knife driving arm 53 and the first rotating piece 64 (also referred to as a first L-shaped rotating link) of the knife position adjusting body 59, and connects the output portion 53 b of the knife driving arm 53. It has a function of transmitting an advancing / retreating operation substantially along the X-axis direction to the rotating end portion of the first rotating piece 64. By the way, the output portion 53b of the knife drive arm 53 is displaced in the X-axis direction and the Z-axis direction by the rotation operation, and the first rotation piece 64 is moved in the X-axis direction and the Y-axis direction by the rotation operation. Displacement occurs. Further, the position of the knife drive arm 53 is also switched along the support shaft 54 (Y-axis direction). As described above, since both ends of the first link body 58 are displaced in all directions, the both ends are connected to the knife driving arm 53 and the first rotating piece 64 through the spherical bearings 58a and 58b, respectively. Has been. Thereby, even when displacement occurs in each direction at both ends, it is possible to smoothly transmit the operation.
The link body 58 is substantially orthogonal to the shuttle shaft 11 and is disposed between the shuttle shaft 11 and the sewing machine bed upper surface 2a.

  On the other hand, a second link body (also referred to as a moving knife drive link) 61 connects the second rotating piece 65 of the knife position adjusting body 59 and the operating arm 34 of the thread trimming device 30 to the second rotation. The moving piece 65 has a function of transmitting the advancing / retreating operation substantially along the Y-axis direction to the rotating end of the first operating arm 34. Since both the second rotating piece 65 and the operating arm 34 are displaced by the rotation in the X-axis direction and the Y-axis direction, they coincide with each other. I don't need it.

(Control device)
Next, a control device 100 as control means for the sewing machine 10 and a control system for the sewing machine 10 related thereto will be described with reference to FIG.
The control device 100 includes a ROM 102 storing various programs and various setting data for executing various controls of the sewing machine 10 to be described later, a CPU 101 executing various programs in the ROM 102, and executing each program of the CPU 101. A RAM 103 that temporarily stores data and serves as a work area, an EEPROM 104 that stores various types of data that can be changed and predetermined programs, the drive circuit 105 of the sewing machine motor 1 described above, and various commands and settings for the sewing machine. The operation panel 109 for inputting the thread, its interface circuit 106, the thread trimming drive circuit 107 of the thread trimming solenoid 56 described above, and a speed (not shown) for inputting execution of sewing start, interruption, thread trimming, etc. Speed change provided on the change pedal (hereinafter simply referred to as pedal) And a pedal sensor 108.
The output shaft of the sewing machine motor 1 is provided with an encoder 14 that outputs a pulse in a minute angle unit, and the main shaft that is rotationally driven by the sewing machine motor 1 is provided with a needle position detector 15 that outputs a signal at a predetermined angle. It has been. These are all connected to the CPU 101, and the CPU 101 can always detect the shaft angle of the spindle from these outputs. That is, they function as “position detectors”.

(Sewing control)
Next, the sewing control executed by the CPU 101 using the sewing control program stored in the ROM 102 will be described. FIG. 7 is a flowchart of the sewing control.
Here, the pedal described above has a neutral position in the stepping operation, and can be stepped forward and stepped backward using the neutral position as a reference. Then, the control device 100 detects an input operation to the pedal from the speed changing pedal sensor 108 and executes sewing control in accordance with the detected input operation. That is, when the pedal is stepped forward, a sewing operation is performed by rotationally driving the sewing machine motor 1, and when the pedal is returned to the neutral position from the sewing operation state, the lower stop position (the needle bar lower dead center is passed). The sewing machine motor 1 is stopped at the main shaft angle at which the hook's sword tip begins to catch the sewing thread. In addition, when the pedal is further stepped down after returning to the neutral position, the first thread trimming control is performed, and when the pedal is directly stepped back from the forward stepped state without stopping at the neutral position, Second thread trimming control is performed. The first and second thread trimming controls will be described later.

In the sewing-ready state of the sewing machine 10, the CPU 101 detects the front depression of the pedal (step S11). When the front depression of the pedal is performed, the sewing machine motor 1 is driven to rotate at a rotational speed corresponding to the depression amount. Sewing is started (step S12).
During sewing, the neutral position of the pedal is detected (step S13). When the operation of the neutral position is detected, the CPU 101 stops the driving of the sewing machine motor 1 at the lower stop position (step S14). That is, when the operation of the neutral position is detected, the CPU 101 decelerates the sewing machine motor 1 and detects the spindle angle indicating the lower stop position from the outputs of the needle position detector 15 and the encoder 14 (referred to as the needle position detector 15 etc.). The sewing machine motor 1 is stopped after waiting.

Then, the CPU 101 detects the front depression of the pedal while the sewing machine motor 1 is stopped (step S15). When the front depression is detected, the process returns to step S12 to drive the sewing motor 1. Continue sewing again.
Further, when the front step is not detected, the rear step is detected (step S16). When the front step is not detected, the process returns to step S15 to enter the front step detection state. On the other hand, when the rear stepping is detected, the CPU 101 executes the first thread trimming control (step S17), and then ends the sewing.

On the other hand, when the neutral position is not detected in the position detection of the pedal in step S13, the CPU 101 detects whether or not the direct backward stepping is performed from the front stepping state (step S18).
If the backward stepping is not performed, the process returns to step S13 to detect the neutral position again. If the backward stepping is performed, the CPU 101 executes the second thread trimming control (step S19), and then Finish sewing.

(First cutting control)
Next, the first cutting control executed by the CPU 101 using the first cutting control program stored in the ROM 102 will be described. FIG. 8 is a diagram showing changes in the needle bar height (vertical axis) with respect to the main shaft angle (horizontal axis).
The first cutting control will be described on the assumption that the top dead center of the needle bar is 0 ° and the bottom dead center is 180 ° as shown.
In the first cutting control, the operation of the thread trimmer solenoid 56 is started in a state where the sewing machine motor 1 is stopped with the lower stop position as a target stop position, and the roller 52 is caused to enter the cam groove 51a of the thread trimmer cam 51. In this control, after a predetermined delay time (waiting time) has elapsed from the start of driving of the thread trimming solenoid 56, the sewing machine motor 1 is driven again to perform thread trimming.

The thread trimming solenoid 56 has a time lag from when it receives a drive start command due to the influence of a load or the like until it actually starts driving. Further, when the roller 52 is inserted into the cam groove 51a, it vibrates due to a reaction. It can be said that the engaged state (connected state) is completed only after the vibration has stopped. That is, it takes time until the above-described time lag and vibration are settled from the start of driving of the thread trimming solenoid 56 to completion.
Further, when the sewing machine motor 1 is stopped at the lower stop position, the actual stop position varies depending on various conditions, and varies in the range of 215 ° to 250 ° (lower stop section).

On the other hand, the roller 52 of the thread trimming drive mechanism 50 can be engaged by insertion only with respect to the non-displacement section of the cam groove 51a of the thread trimming cam 51, and the displacement section (cam operation section) of the cam groove 51a. ) Has a structure in which the roller 52 is displaced and cannot be inserted. Therefore, it is necessary to complete the engagement operation of the roller 52 with the cam groove 51a by the thread trimming solenoid 56 until the displacement section of the cam groove 51a is reached by the restart driving of the sewing machine motor 1.
Accordingly, when the sewing machine motor 1 is stopped at the lower stop position, if the actual stop position is shifted to the displacement section side (for example, when stopped at 250 °), the completion of the engagement operation of the roller 52 may not be in time. .

Further, the rotational speed (thread trimming set rotational speed v1) at the time of resuming driving of the sewing machine motor 1 can be arbitrarily set in the range of 160 to 680 [rpm], and the set value is the EEPROM 104. And is read out when the first cutting control is executed.
Even when the resumption drive speed is set to a high speed (for example, 680 [rpm]), the engagement operation of the rollers 52 may not be completed in time.

Therefore, in the first cutting control, the above problem is solved by adjusting the delay time (waiting time) from the start of driving of the thread trimming solenoid 56 to the restarting driving of the sewing machine motor 1.
That is, in the first cutting control, the CPU 101 detects the lower stop angle θ1 that is the actual stop position in the lower stop section of the sewing machine motor 1 from the outputs of the encoder 14 and the position detector 15, and also sets the thread trimming set rotational speed. The value of v1 is read, and an appropriate delay time is specified from a table as shown in FIG. 9 using these two parameters. The difference between the delay times is provided to drive the thread trimming solenoid 52 and the sewing machine motor 1, and the engagement operation of the rollers 52 is executed without excess or deficiency to perform thread trimming.

In the above table, the delay time (unit: ms) is set longer as the lower stop angle θ1 approaches the cam operation section, and the delay time is set longer as the thread trimming rotation speed v1 becomes faster. The Also, a blank means zero delay time.
Note that the above table may be created by repeating the actual measurement test and acquiring appropriate delay times for the two parameters, or in the lower stop section when the sewing machine motor 1 is driven at each thread trimming set rotational speed. It is also possible to obtain the appropriate delay time by calculating the time required to reach the cam operation section from each spindle angle.
In addition, the delay time may be specified by referring to the table as described above, and may be calculated by the above calculation when the first cutting control is executed each time.

FIG. 10 is a flowchart showing the first cutting control. The first cutting control executed by the CPU 101 by executing the first cutting control program will be described in order.
First, in a state where the sewing machine motor 1 has already stopped in the lower stop section, the CPU 101 detects the actual lower stop angle θ1 from the outputs of the encoder 14 and the needle position detector 15 (step S31). Further, the set value of the thread trimming set rotational speed v1 stored in the EEPROM 104 is read (step S32).
Further, referring to the table, the delay time T is determined from the lower stop angle θ1 and the thread trimming set rotational speed v1 (step S33).

  Next, the CPU 101 drives the thread trimming solenoid 56 (step S34) and measures the elapsed time from the driving (step S35). Then, it is determined whether or not the elapsed time t exceeds the delay time T (step S36). If the delay time T has elapsed, the sewing machine motor 1 is driven at the thread trimming set rotational speed v1 (step S37).

By driving the thread trimming solenoid 56, the hook thread presser 13 is operated via the connecting link member 63, and the rotation of the bobbin accommodated in the inner hook of the hook mechanism is prevented.
Further, the thread tension releasing portion 55b of the clutch member 55 pulls the release wire 12 and releases the thread tension device for the upper thread.
Further, the contact portion 55a of the clutch member 55 presses the position restricting projection 53d of the knife driving arm 53 to the left and moves it to the outside of the recess 57a, and moves the roller 52 in the cam groove 51a of the thread trimming cam 51. To enter. At this time, the cam groove 51a has a non-displacement section at the entry position of the roller 52, and the roller 52 smoothly enters the cam groove 51a and the engaging operation is performed. The second stopper 60 has been adjusted in advance.
When the sewing machine motor 1 is restarted, the thread trimming cam 51 rotates as the vertical feed shaft 22 rotates, and when the roller 52 reaches the cam operating section, the knife driving arm 53 is counterclockwise as viewed from the right side. The knife position adjusting body 59 is rotated clockwise through the first link body 58 in a bottom view. As a result, the connecting end of the operating arm 34 of the thread trimming device 30 is rotated to the right via the second link body 61 so that the moving knife 31 is moved backward from the standby position (see FIG. 3). Move from the position of moving knife on the two-dot chain line to the position of the solid line) As a result, the moving knife 31 passes through the needle drop position and selects the thread to be cut.
Further, when the thread trimming cam 51 rotates, the roller moves so as to return to the latter half of the displacement section, that is, the non-displacement section. As a result, the knife driving arm 53 rotates clockwise in a right side view, The female position adjusting body 59 rotates counterclockwise through the one link body 58 in a bottom view. As a result, the connecting end of the operating arm 34 of the thread trimming device 30 is rotated to the left via the second link body 61 so that the moving knife 31 is advanced from the retracted position toward the standby position. (Move from the position of the moving knife of the solid line in FIG. 3 to the position of the two-dot chain line). As a result, the moving knife 31 passes through the needle drop position again, and further carries the thread to be cut to the blade part 33a of the fixed knife 33 to execute cutting.

  Thereafter, the CPU 101 detects the upper stop angle θ2 from the outputs of the encoder 14 and the needle position detector 15 (step S38), and the current angle has reached the set spindle angle (for example, 53 °) of the upper stop position θ2. (Step S39). If not reached, the process returns to step S38, and the output detection of the encoder 14 and the needle position detector 15 is repeated. If reached, the sewing machine motor 1 is stopped (step S40) and the thread trimmer solenoid 56 is driven. Stop (step S41). Thereby, the first cutting control ends.

(Second cutting control)
Next, the second cutting control executed by the CPU 101 using the second cutting control program stored in the ROM 102 will be described with reference to FIGS. 8, 11, and 12. FIG.
The second cutting control is a control for executing thread trimming without temporarily stopping the sewing machine motor 1 during the sewing operation, and is a preset rotation speed at the time of executing thread trimming of the sewing machine motor 1. By determining the solenoid operating angle θ3, which is the main shaft angle at which the thread trimming solenoid 56 starts to be driven, in accordance with the thread trimming set rotational speed v2, and starting the thread trimming solenoid 56 at the solenoid operating angle θ3, the thread trimming solenoid 56 is started. The target position A (see FIG. 8, for example, 230 °) at which the main shaft angle for completing the engagement operation of the roller 52 with the cam groove 51a is constant regardless of the value of the cut setting rotation speed v2. It is trying to become.

As described above, the thread trimming solenoid 56 requires a time lag and a time until vibration is settled from the start to the completion of driving.
The rotational speed (thread trimming set rotational speed v2) of the sewing machine motor 2 in the second cutting control can be arbitrarily set from the operation panel 109 within a range of 180 to 500 [rpm], and the set value Is stored in the EEPROM 104 and is read when the second cutting control is executed.
Although the time required to complete the operation of the thread trimming solenoid 56 is constant, the rotational speed of the sewing machine motor 1 (thread trimming rotation speed v2) can be set to an arbitrary value. When the driving start timing (main shaft angle) is constant, the timing at which the engagement operation of the roller 52 by the thread trimming solenoid 56 is completed varies according to the thread trimming set rotational speed v2 of the sewing machine motor 1. It becomes. In this case, when the thread trimming set rotational speed v2 of the sewing machine motor 1 is high, the timing for completing the engagement operation of the roller 52 by the thread trimming solenoid 56 is delayed and cannot be completed until the start of the cam operation section described above. Create a possibility. Further, when the thread trimming set rotational speed v2 of the sewing machine motor 1 is low, the timing for completing the engagement operation of the roller 52 by the thread trimming solenoid 56 becomes too fast, and the hook thread presser 13 interlocked with the roller 52 The hook presser operation is also executed quickly, and the hook thread presser 13 may interfere (contact) with the sewing needle that is not sufficiently raised. The main shaft angle at which the hook thread presser 13 may interfere (contact) with this sewing needle is in the range of 155 ° to 205 °.

Accordingly, in this second cutting control, the timing (spindle angle) for starting the driving of the thread trimming solenoid 56 is individually changed and adjusted according to the thread trimming setting speed v2 of the sewing machine motor 1 so that the set speed v2 is The spindle angle is individually determined so that the start of driving of the thread trimmer solenoid 56 is advanced if the speed is high, and the start of driving of the thread trimmer solenoid 56 is delayed if the set speed v2 is low, and the set speed v2 is set to any of them. Even in such a case, the timing at which the engagement operation of the roller 52 by the thread trimming solenoid 56 is completed is set to a constant target position A.
The target position A is a first section that is an intermediate section from the main shaft angle at which the hook thread presser 13 does not contact the sewing needle (non-contact section 205 °) to the main shaft angle (285 °) at which the cam operation section starts. It is preferable that the predetermined section (220 ° to 260 °) is set.
Since the hook thread presser 13 is biased by a spring (not shown), damping (vibration) occurs when the hook thread presser 13 presses the bobbin. Due to this damping, a gap is generated between the hook thread presser 13 and the bobbin, and when the thread is pulled up, the thread is not locked to the hook thread presser 13 and the remaining thread length on the needle side is shortened. May occur.
In order to prevent this, the target position A is set to a second predetermined section (220 ° to 240 °) in which the target position at which the roller engagement operation is completed is set earlier in consideration of the time during which damping is settled. More preferred.
Furthermore, it is more preferable that the engagement operation of the roller 52 by the thread trimming solenoid 56 is completed at a predetermined main shaft angle (for example, 230 °) in the middle.

The timing (main shaft angle) at which the thread trimming solenoid 56 starts to be driven for each thread trimming rotation speed v2 of the sewing machine motor 1 is determined in the table shown in FIG. 11, and the table is prepared in the EEPROM 104 in advance. ing.
In the above table, it is determined that the timing for starting the driving of the thread trimming solenoid 56 is delayed as the thread trimming set rotational speed v2 is decreased.
Note that the above-described table may be created by repeating the actual measurement test and acquiring the appropriate drive start timing of the thread trimming solenoid 56 with respect to the thread trimming set rotational speed v2, or at each thread trimming rotational speed v2. The time required to reach the target position A when driving 1 may be obtained by calculation, and an appropriate drive start timing of the thread trimming solenoid 56 may be obtained by calculation.
In addition, the delay time may be specified by referring to the table as described above, and may be calculated by the above calculation when the second cutting control is executed each time.

FIG. 12 is a flowchart showing the second cutting control. The second cutting control executed by the CPU 101 by executing the second cutting control program will be described in order.
First, the CPU 101 reads the set value of the thread trimming set rotational speed v2 stored in the EEPROM 104 (step S61), and performs control to decelerate the sewing machine motor 1 to the read thread trimming set rotational speed v2 (step S61). Step S62).
Further, referring to the table, the solenoid operating angle θ3 is determined from the thread trimming set rotational speed v2 (step S63).

The CPU 101 detects the current main shaft angle θ from the outputs of the encoder 14 and the needle position detector 15 (step S64), and determines whether the current main shaft angle θ has reached the solenoid operating angle θ3 (step S65). If not reached, the process returns to step S64, and the output detection of the encoder 14 and the needle position detector 15 is repeated, and if reached, the thread trimming solenoid 56 is driven (step S66).
By driving the thread trimming solenoid 56, the thread trimming device 30 and the thread trimming drive mechanism 50 operate in the same manner as in the first cutting control, and execute the cutting of the sewing thread.

  Thereafter, the CPU 101 detects the upper stop angle θ2 from the outputs of the encoder 14 and the needle position detector 15 (step S67), and the current angle has reached the set spindle angle (for example, 53 °) of the upper stop position θ2. (Step S68). If not reached, the process returns to step S67, and the output detection of the encoder 14 and the needle position detector 15 is repeated. If reached, the sewing machine motor 1 is stopped (step S69) and the thread trimmer solenoid 56 is driven. Stop (step S70). Thereby, the second cutting control ends.

(Effect of the embodiment of the invention)
In the sewing machine 10, in the first cutting control, the start of driving of the sewing machine motor 1 is delayed from the start of driving of the thread trimming solenoid 56 according to the delay time T determined by the lower stop angle θ1 and the thread trimming set rotational speed v1. Therefore, it can be avoided and reduced that the cam operation section (displacement section) of the thread trimming cam 51 is reached before the engagement of the roller 52 with the cam groove 51a is completed. Accordingly, since the restart start timing of the sewing machine motor 1 is adjusted, an unnecessary delay can be avoided, and it is possible to optimize the cam follower connection operation.

  Further, in the sewing machine 10, in the second cutting control, since the driving of the thread trimming solenoid 56 is started according to the solenoid operating angle θ3 determined by the thread trimming set rotational speed v2, the thread trimming rotational speed v2 is set to any value. Further, the completion of the engagement operation of the roller 52 by the thread trimming solenoid 56 can be set to a certain target position A, and the thread trimmer 56 is driven too early, and the interference between the sewing needle and the hook thread presser 13 is also caused by the thread trimming. A delay in the engagement operation of the roller 52 due to the drive of the solenoid 56 being too slow can be effectively avoided, and a stable thread trimming operation can be performed.

(Other)
The sewing machine 10 employs a cam mechanism having a structure in which the roller 52 moves along the direction of the rotation axis of the thread trimming cam 51 and engages with the cam groove 51a. You may employ | adopt the cam mechanism of the structure which opens toward a rotation radial direction outer side, and a roller moves toward the rotation radial direction inner side from the said opening part, and engages. In this case, the roller 52 is not engageable only when the cam groove is in the non-displacement section as in the cam mechanism described above, but the roller can be engaged only in the section where the opening is open. Therefore, the start timing of the rotational drive of the sewing machine motor 1 relative to the start of driving of the thread trimming solenoid 56 is also an important point, and as in the above example, the detected main shaft angle at the time of stopping at the lower stop position of the sewing machine motor 1 By appropriately adjusting the waiting time based on the restart driving speed of the sewing machine motor 1, it is possible to optimize the roller connecting operation with respect to the thread trimming cam.

  In the first cutting control, the delay time T is determined by both the lower stop angle θ1 and the thread trimming set rotational speed v1, but only one of the lower stop angle θ1 and the thread trimming set rotational speed v1 is determined. The delay time may be determined by When the delay time is determined by the lower stop angle θ1, the thread trimming set rotational speed v1 cannot be changed and adjusted to an arbitrary value, and the cutting may always be performed at a constant rotational speed.

In the first cutting control, the delay time T is controlled based on the lower stop angle θ1 and the thread trimming set rotational speed v1, but the thread trimming set rotational speed v1 can be arbitrarily changed and adjusted. The controller 100 determines an appropriate thread trimming set rotational speed v1 based on the detected lower stop angle θ1, and restarts the sewing machine motor 1 at the thread trimming rotational speed v1 to control the sewing thread cutting control. You can go.
In that case, the EEPROM 104 of the control device 100 is provided with a table in which appropriate thread trimming set rotational speeds V1 to V12 are set for each value of the lower stop angle θ1 detected in advance (see FIG. 13). It is desirable to determine the thread trimming set rotational speed v1 with reference to FIG. In addition to using the table, the cam operation section is reached from the lower stop angle θ1 based on the required time from the start of driving of the thread trimming solenoid 56 to the completion of engagement of the roller 52 and the detected lower stop angle θ1. The thread trimming set rotational speed v1 that does not cause a delay in completion of the engagement of the rollers 52 may be calculated by calculation according to the rotational angle up to.
The content of the control of another example of the first cutting control will be described based on the flowchart shown in FIG.

First, in a state where the sewing machine motor 1 has already stopped in the lower stop section, the CPU 101 detects the actual lower stop angle θ1 from the outputs of the encoder 14 and the needle position detector 15 (step S81). Then, with reference to the table, the thread trimming set rotational speed v3 is determined from the lower stop angle θ1 (step S82).
Then, the sewing machine motor 1 is driven at the thread trimming set rotational speed v3 without providing the delay time T as described above (step S83).
As a result, the sewing thread is cut.
Thereafter, the CPU 101 detects the upper stop angle θ2 from the outputs of the encoder 14 and the needle position detector 15 (step S84), and the current angle reaches the set spindle angle (for example, 53 °) of the upper stop position θ2. (Step S85). If not reached, the process returns to step S84, and the output detection of the encoder 14 and the needle position detector 15 is repeated. If reached, the sewing machine motor 1 is stopped (step S86) and the thread trimmer solenoid 56 is driven. Stop (step S87). Thereby, the first cutting control ends.
As described above, even when such first cutting control is performed, it is possible to obtain the same effect as in the case of the first cutting control that determines the delay time described above.

1 sewing machine motor 10 sewing machine 11 hook shaft 14 encoder (position detector)
15 Needle position detector (position detector)
20 Cloth feeding device 30 Thread trimming device 31 Moving knife 50 Thread trimming drive mechanism 51 Thread trimming cam 51a Cam groove 52 Roller (cam follower)
56 Thread trimming solenoid 100 Control device (control means)
101 CPU

Claims (2)

A sewing machine motor as a drive source for the vertical movement of the needle bar holding the sewing needle;
A thread trimming device that performs thread cutting using the power of the sewing machine motor;
Control means for controlling the thread trimming device and a sewing machine motor;
A position detector for detecting an angle of a main shaft that is rotationally driven by the sewing machine motor;
Speed setting means for setting the rotational speed of the sewing machine motor at the time of the yarn cutting,
The thread trimming device includes a thread trimming cam that is rotated by the sewing machine motor, a cam follower that performs a driven operation according to a cam groove of the thread trimming cam, and a thread cutting operation that is interlocked with the cam follower. A moving knife, a thread trimmer solenoid for switching the cam follower from a non-coupled state to a coupled state with respect to the thread trimmer cam, and a bobbin inside the hook interlocked with the cam follower by the thread trimmer solenoid. And a hook presser that stops against rotation
In the sewing machine which performs thread trimming control in which the control means drives the sewing machine motor at a rotational speed determined by the speed setting means and switches to a connected state by the thread trimming solenoid.
First thread trimming control for performing thread trimming after temporarily stopping the sewing machine motor and second thread trimming control for performing thread trimming without temporarily stopping the sewing motor. Can be entered selectively,
The control means includes
In the first thread trimming control, a waiting time from the start of driving the thread trimming solenoid to the restart driving of the sewing machine motor is determined according to the lower stop angle when the sewing machine motor is stopped and the setting of the thread trimming set rotational speed. And
In the second thread trimming control, an appropriate operation is performed according to the rotational speed determined by the speed setting means so that the switching operation of the cam follower by the thread trimming solenoid is completed at a constant spindle angle. A main shaft angle serving as an operation start timing of the thread trimming solenoid is determined, and the operation start control of the thread trimming solenoid is performed at the main shaft angle.   The constant spindle angle at which the control means completes the operation of switching the cam follower to the connected state by the thread trimmer solenoid is determined from the spindle angle at which the hook presser does not cause interference with the sewing needle. 2. The sewing machine according to claim 1, wherein the sewing machine is set to a predetermined section until a main shaft angle at which the cam follower cannot be switched to a connected state.

Images