JP5925603B2 - sewing machine - Google Patents

Description

  The present invention relates to a sewing machine that shortens the remaining end after thread trimming.

The conventional sewing machine includes a feed dog on the lower side of the needle plate, and a thread trimming device for cutting the upper thread and the lower thread is further provided on the lower side of the feed dog.
In addition, the feed dog draws a substantially elliptical trajectory along the major axis in the feed direction and makes a circular motion.When passing through the upper part of the ellipse, the upper end of the feed dog protrudes from the upper surface of the needle plate, It was possible to send in a predetermined feed direction.
In addition, the feed mechanism that imparts the orbiting motion to the feed dog can adjust the feed direction and the width of the feed direction in the trajectory of the orbiting motion by an actuator, and can be controlled by the control device during the sewing operation. The feed pitch can be arbitrarily changed, and the forward / reverse feed direction can be switched.

  By the way, in the sewing machine, when the sewing is finished, the upper thread and the lower thread are automatically cut by the thread trimming device. However, if the remaining ends of the upper thread and the lower thread at the end of the seam after the cutting are long, the sewing quality Therefore, shortening these remaining ends has been an important issue for sewing machines that perform automatic positioning.

  For this reason, in the prior art described in Patent Document 1, the needle drop is performed by shortening the feed pitch as much as possible after the needle drop (final knot point) in which the upper thread and the lower thread are intertwined to form the final knot, It has been proposed to cut the upper and lower threads that have been captured during the fall. In this sewing machine, since the thread trimming device is arranged so that the thread cutting position is almost directly below the sewing needle, the remaining ends of the upper thread and the lower thread are arranged so that the thread cutting position is as close as possible from the final knot. The length is shortened.

  Further, in the prior art described in Patent Document 2, in the case of the needle feed sewing machine, in view of the fact that the thread trimming device cannot be arranged so that the thread cutting position comes almost directly below the sewing needle, Remaining edge after cutting by shortening the remaining length by moving the feed dog backward by 3/4 of the sewing pitch while moving the feed dog away from the cloth on the needle plate and bringing the needle hole of the feed dog closer to the cutting part Can be shortened.

  Further, the prior art described in Patent Document 3 discloses a sewing machine in which a thread trimming device includes a hooking knife and a cutting knife, and both of them move to perform cutting. When this thread trimming device of a sewing machine is applied to a needle feed sewing machine, thread trimming can be performed at the center of needle swing, and the remaining end can be shortened.

Japanese Patent Laid-Open No. 04-024092 Japanese Patent No. 4020692 Japanese Patent No. 4164157

  The thread trimming device described in Patent Document 1 is an invention that is directed to a sewing machine in which the needle bar does not swing and the needle bar is moved at a fixed needle drop position, and is applied to a sewing machine in which the needle bar swings. In order to avoid interference with the sewing needle, the fixed knife must be arranged at a position away from the needle drop position by more than the maximum setting width × 1/2 of the sewing pitch. For this reason, even if the feed pitch is shortened as much as possible after the final knot and needle dropping is performed, the remaining end of the sewing thread cannot be shortened.

  The thread trimming device described in Patent Document 2 is designed in consideration of needle feed, but by moving the feed dog reversely by 3/4 of the sewing pitch, the needle hole of the feed dog is brought close to the cutting portion. Therefore, the proximity width of the feed dog to the cutting part depends on the set width of the feed pitch. If the set pitch is small, the feed dog cannot be brought close enough and the remaining end of the sewing thread must be shortened. I could not.

  The yarn trimming device described in Patent Document 3 requires a configuration for moving both the hooking knife and the cutting knife of the yarn trimming device, and there is a problem in that the configuration is complicated and the number of parts is increased.

  An object of the present invention is to shorten the remaining end of the sewing thread without causing a complicated structure and an increase in the number of parts.

According to the first aspect of the present invention, an upper shaft that is rotationally driven by a sewing machine motor, a needle bar vertical movement mechanism that moves the needle bar up and down in synchronization with the rotation of the upper shaft, and in synchronization with the rotation of the upper shaft. A needle feed mechanism that swings the needle bar along the cloth feed direction, and a feed dog with a needle hole that circulates in an elliptical locus along the cloth feed direction in synchronization with the rotation of the upper shaft. The cloth feed mechanism that feeds the workpiece to be sewn, the thread trimming device that cuts the upper thread and the lower thread on the downstream side in the positive cloth feed direction with respect to the sewing needle supported by the needle bar, and the sewing pitch is adjusted. A feed amount adjusting mechanism; and a control device for controlling the operation of the thread trimming device and the feed amount adjusting mechanism, and the cloth feed by the feed dog in a state in which the sewing needle is lowered and pierced through the workpiece. In the sewing machine that performs
The control device sets the feed pitch as the minimum pitch that can be adjusted by the feed amount adjusting mechanism in the forward or reverse cloth feed direction in a state where the sewing needle forming the seam of the final knot is stuck in the workpiece. The feed pitch can be adjusted by the feed amount adjustment mechanism in the positive cloth feed direction with the sewing needle fed after the last knot and the sewing needle stuck in the work piece. The sewing product is fed as a maximum pitch, and the feed pitch that is fed at the maximum pitch is set in the reverse cloth feeding direction until the feed dog is separated from the sewing product and before thread trimming is performed. The feed amount adjusting mechanism is controlled so as to move the feed dog as a maximum pitch adjustable by the feed amount adjusting mechanism.

According to a second aspect of the present invention, there is provided an upper shaft that is rotationally driven by a sewing machine motor, a needle bar vertical movement mechanism that moves the needle bar up and down in synchronization with the rotation of the upper shaft, and in synchronization with the rotation of the upper shaft. A needle feed mechanism that swings the needle bar along the cloth feed direction, and a feed dog with a needle hole that circulates in an elliptical locus along the cloth feed direction in synchronization with the rotation of the upper shaft. A cloth feed mechanism that feeds the work to be sewn, a thread trimming device that cuts the upper thread and lower thread upstream of the sewing needle supported by the needle bar in the positive cloth feed direction, and a sewing pitch is adjusted. A feed amount adjusting mechanism; and a control device for controlling the operation of the thread trimming device and the feed amount adjusting mechanism, and the cloth feed by the feed dog in a state in which the sewing needle is lowered and pierced through the workpiece. In the sewing machine that performs
The control device sets the feed pitch as the minimum pitch that can be adjusted by the feed amount adjusting mechanism in the forward or reverse cloth feed direction in a state where the sewing needle forming the seam of the final knot is stuck in the workpiece. The feed pitch can be adjusted by the feed amount adjustment mechanism in the reverse cloth feed direction with the sewing needle fed after the last knot point being stuck in the work piece while feeding the sewing product. The sewing product is fed as a maximum pitch, and the feed pitch that is fed at the maximum pitch is separated from the sewing product until thread trimming is performed. The feed amount adjusting mechanism is controlled so as to move the feed dog as a maximum pitch adjustable by the feed amount adjusting mechanism.

According to the first aspect of the present invention, when thread trimming is performed on the downstream side in the positive cloth feed direction, the feed pitch is set forward or reverse with the sewing needle forming the seam of the final knotting point stuck in the workpiece. The sewing material is fed as the minimum pitch that can be adjusted by the feed amount adjusting mechanism in the cloth feeding direction. For example, if the range from the lower limit value to the upper limit value of the normal sewing pitch width by the feed amount adjusting mechanism is predetermined in the control device, the lower limit value can be adjusted by the “feed amount adjusting mechanism”. The sewing machine has functions such as special sewing other than normal sewing, such as condensation sewing, which is sewing at a minute pitch to prevent fraying of the sewing thread at the beginning and end of sewing. If the pitch width of the condensation sewing is smaller than the lower limit value of the normal sewing pitch width, the condensation sewing pitch is set as the “minimum pitch adjustable by the feed amount adjusting mechanism”. Also good. In addition, even with a sewing machine that does not perform condensation sewing, a fine pitch that cannot be formed by normal sewing that deviates from the range from the lower limit value to the upper limit value of the normal sewing pitch width can be adjusted with the `` feed amount adjustment mechanism ''. The “minimum pitch” may be determined separately from the normal sewing pitch width. In any case, these “minimum pitches” are required to be other than zero.
As described above, the seam is formed at the normal feed pitch up to the final knot point, and the next stitch is fed at the minimum pitch adjustable by the feed amount adjusting mechanism. The feed pitch when the next needle drop is performed is the maximum pitch that can be adjusted in the forward direction by the feed amount adjustment mechanism, so that the needle drop position is moved to the thread trimming position side to the maximum. be able to.
Furthermore, the feed dog starts to move away from the thread trimming position when it is separated from the workpiece, but at this time, the feed dog is controlled to have a maximum pitch that can be adjusted by the feed amount adjusting mechanism in the reverse cloth feed direction. Therefore, the feed dog moves again toward the thread trimming position, and the feed dog can be moved to the thread trimming position side to the maximum extent before the thread trimming is executed.
As a result, the path length from the needle drop position of the minimum pitch to the thread trimming position through the needle hole of the feed dog can be shortened to the maximum, and the remaining end after thread cutting is made possible while allowing needle swinging. Can be made shorter.
In addition, the remaining end after thread cutting can be made shorter than before, regardless of the sewing pitch during sewing.

In the invention of claim 2, when thread trimming is performed on the upstream side in the positive cloth feed direction, the feed pitch is set to be normal or reverse in a state where the sewing needle forming the stitch of the final knot is stuck in the workpiece. The sewing material is fed as the minimum pitch that can be adjusted by the feed amount adjusting mechanism in the cloth feeding direction. An example of “minimum pitch” is the same as in the case of claim 1.
When the next needle drop is performed, the maximum pitch is adjusted by the feed amount adjusting mechanism in the reverse direction, and when the feed dog is separated from the workpiece, it is adjusted by the feed amount adjusting mechanism in the positive cloth feeding direction. It is controlled to be the maximum possible pitch.
As a result, the needle entry position and feed dog at the minimum pitch of the workpiece can be moved to the thread trimming position as much as possible, and from the needle entry position at the minimum pitch to the thread trimming position via the needle hole of the feed dog. Can be shortened to the maximum. Accordingly, it is possible to make the remaining end after the yarn cutting shorter than before while enabling the needle swing.
In addition, the remaining end after thread cutting can be made shorter than before, regardless of the sewing pitch during sewing.

It is a mechanism diagram of the needle feed sewing machine which is the first embodiment. It is a disassembled perspective view of a cloth feed mechanism. It is a side view which shows a feed amount converter. It is a schematic explanatory drawing which shows the structure of a horizontal feed mechanism. It is a disassembled perspective view showing the relationship between a feed amount conversion body and a feed adjustment motor. It is a perspective view of a thread trimming device. It is a block diagram which shows the control system of a sewing machine. It is a flowchart at the time of sewing of the sewing machine and execution of thread trimming. It is operation | movement explanatory drawing at the time of the thread trimming of a sewing machine, and has shown the case where operation | movement advances in order of FIG. 9 (A)-FIG. 9 (E). FIG. 10 is an operation explanatory diagram when executing thread trimming of the sewing machine continued from FIG. 9, and shows a case where the operation proceeds in the order of FIG. 10 (F) to FIG. 10 (J). It is explanatory drawing which shows the position change of a feed dog. It is operation | movement explanatory drawing which shows the other operation example at the time of thread trimming of a sewing machine, and shows the case where operation | movement advances in order of FIG. 12 (A)-FIG.12 (E). FIG. 13 is an operation explanatory view when the thread is trimmed from the sewing machine continued from FIG. 12, and shows a case where the operation proceeds in the order of FIG. 13 (F) to FIG. 13 (J). It is explanatory drawing which shows the position change of the feed dog in the other operation example at the time of thread trimming of a sewing machine. It is operation | movement explanatory drawing at the time of the thread trimming execution of the sewing machine in 2nd embodiment, and shows the case where operation | movement advances in order of FIG. 15 (A)-FIG. 15 (E). FIG. 16 is an operation explanatory diagram when executing thread trimming of the sewing machine continued from FIG. 15, and shows a case where the operation proceeds in the order of FIG. 16 (F) to FIG. 16 (J). It is explanatory drawing which shows the position change of the feed dog of the sewing machine in 2nd embodiment. It is a mechanism diagram of another feed adjustment mechanism. It is operation | movement explanatory drawing made into the setting sewing pitch of another feed adjustment mechanism. It is operation | movement explanatory drawing made into the maximum sewing pitch of the reverse feed of another feed adjustment mechanism. It is operation | movement explanatory drawing made into the condensation sewing pitch of another feed adjustment mechanism. It is operation | movement explanatory drawing made into the maximum sewing pitch of the forward feed of another feed adjustment mechanism.

[First embodiment]
Hereinafter, a first embodiment of the present invention will be described in detail with reference to FIGS. In this embodiment, a needle feed sewing machine will be described as an example of the feed mechanism of the sewing machine. The needle feed sewing machine is a needle bar needle that synchronizes with the feed dog, for example, for a workpiece that is difficult to feed precisely according to the set pitch due to slippage or the like caused by a normal feed mechanism, such as a thick material. The sewing machine is capable of swinging and feeding at a set pitch in a state where the sewing needle penetrates the workpiece.
Here, in the following description, the direction along the feed direction (arrow F) is the X-axis direction (front-rear direction), the longitudinal direction of the sewing machine arm 8 orthogonal to the X-axis direction is the Y-axis direction (left-right direction), and the X-axis direction. A direction perpendicular to both the Y-axis direction and the Y-axis direction is defined as a Z-axis direction (vertical direction).

[Overall Configuration of Embodiment]
FIG. 1 is a mechanism diagram of the needle feed sewing machine 1. As shown in FIG. 1, a needle feed sewing machine 1 (hereinafter simply referred to as a sewing machine 1) includes a sewing machine frame 2, an upper shaft 9 as a main shaft that is rotatably supported in the sewing machine frame 2, and the upper shaft 9. The sewing machine motor 60 is a rotational drive source that applies a rotational force to the needle, the needle feed mechanism 14 that drives the needle bar 13 up and down by the drive of the sewing machine motor 60, and swings along the sewing direction F, and the eccentric cam 61. The article to be sewn is fed along the sewing direction F by a horizontal feed rod 49 as a transmission member that gives the needle feed mechanism 14 a reciprocating swinging motion by being driven as a knot, and a feed dog 44 provided below the needle plate. The cloth feed mechanism 30, the needle feed mechanism 14 per one needle, the feed amount adjusting mechanism 51 for adjusting the feed amount by the upper feed mechanism and the cloth feed mechanism 30, and the rotation driving by the lower shaft 37 are not shown. A shuttle mechanism 80, a thread cutting device 70 for cutting the upper thread and lower thread (see FIG. 6), and a control unit 90 for controlling the operation of each of the above structures.

[Configuration on the machine arm side]
First, the configuration of the sewing machine arm 2 on the sewing machine arm 2 side will be described. As shown in FIG. 1, inside the sewing machine arm 8, an upper shaft 9 rotatably supported by the sewing machine arm 8 and a parallel arrangement with respect to the upper shaft 9 are rotatably supported. A needle bar swinging shaft 10 is provided. The upper shaft 9 and the needle bar swinging shaft 10 extend along the Y-axis direction perpendicular to the sewing direction F. A sewing machine motor 60 as a rotational drive source is connected to the upper shaft 9, and the upper shaft 9 rotates as the sewing machine motor 60 rotates.

[Needle feed mechanism]
As shown in FIG. 1, the needle bar swing base 11 is supported by a needle bar swing shaft 10 and can swing about the Y axis. The needle bar rocking base 11 supports a needle bar 13 that holds the sewing needle 13 at its lower end so as to be movable up and down.
The other end of the needle bar swing shaft 10 is connected to a needle bar swing bar 59 that swings at the same cycle as the feed dog 44 synchronized with the vertical movement cycle of the sewing needle 13. The needle bar swinging shaft 10 is connected to the cloth feed mechanism 30 via a needle bar swinging rod 59, thereby swinging the needle bar 13 in synchronization with the feed operation of the feed dog 44. .

Further, when the needle bar swinging base 11 is swung with the rotation of the needle bar swinging shaft 10, the lower end portion of the needle bar 13 is swung in the sewing direction F. That is, the upper shaft 9, the needle bar swinging rod 59, the needle bar swinging shaft 10 and the needle bar swinging base 11 constitute a needle feed mechanism for swinging the needle bar 13 along the sewing direction F.
The needle bar 13 is connected to an eccentric cam 15 attached to the upper shaft 9 via a link member 16, and moves up and down in conjunction with the rotation of the upper shaft 9. In other words, the upper shaft 9, the eccentric cam 15, and the link member 16 constitute a needle bar vertical movement mechanism that applies vertical movement to the sewing needle 13. The needle feed mechanism and the needle bar vertical movement mechanism are interlocked with each other by being driven as the upper shaft 9 is rotated. A needle feed mechanism 14 is configured to feed the sewing product 13 in the sewing direction F in a state in which the product 13 penetrates the sewing product downward.

[Configuration on the machine bed side]
Next, the configuration of the sewing machine frame 2 on the machine bed 50 side will be described. As shown in FIGS. 1 and 2, inside the sewing machine bed 50, a lower shaft 37 that is connected to the upper shaft 9 via pulleys 34, 35 and a belt 36 and rotates in full rotation in conjunction with the upper shaft 9, There are provided a vertical feed shaft 38 and a horizontal feed shaft 39 which are arranged in parallel to the lower shaft 37 and are rotatably supported.

[Cloth feed mechanism]
One end of a vertical feed rod 46 extending in a substantially horizontal direction (X-axis direction) is connected to the lower shaft 37 via an eccentric cam. The other end of the vertical feed rod 46 is connected to the vertical feed shaft 38. It is rotatably connected to a vertical feed shaft arm 45 projecting from the top. The vertical feed shaft 38 has an extending portion 40 that protrudes in the horizontal direction, and one end of a feed base 42 that supports the feed dog 44 rotates through the link member 41 in the extending portion 40. It is connected freely. When the vertical feed rod 46 is swung in the X-axis direction along with the full rotation of the lower shaft 37, the vertical feed shaft 38 reciprocates and the extension portion is moved according to the rotation of the vertical feed shaft 38. A vertical swing is applied to the feed base 42 via the link member 41 and the link member 41.

  Further, a lower end of a horizontal feed rod 49 is rotatably connected to the lower shaft 37 via a circular eccentric cam 61 fixed to the lower shaft 37. The upper end of the horizontal feed rod 49 is pivotally connected to the central portion of a substantially bell-shaped bell crank 48 provided along the X-axis direction above the horizontal feed rod 49. One end of the bell crank 48 is rotatably connected to a horizontal feed shaft arm 47 protruding from the top of the horizontal feed shaft 39, and the other end of the bell crank 48 is connected to a square piece 54 via a support shaft 55. It is rotatably mounted and is slidably connected in a groove 53 of a feed amount conversion body 52 to be described later via the square piece 54. When the horizontal feed rod 49 is swung up and down in accordance with the rotation of the lower shaft 37, the bell crank 48 is moved in the X-axis direction in accordance with the inclination of a groove 53 formed in a feed amount conversion body 52 (described later). And the reciprocating power is applied to the horizontal feed shaft 39. As a result, a horizontal swing is applied to the feed dog 44 supported on the upper portion of the feed base 42 via the feed base arm 43 extending upward from the horizontal feed shaft 39.

  Further, the horizontal feed shaft 39 is provided with a transmission arm 33 extending upward at the end opposite to the feed dog 44 side, and is fixedly connected to the needle bar swinging shaft 10 via the link member 32. Further, the rotational driving force of the horizontal feed shaft 39 is transmitted to the needle bar swing shaft 10 through the needle bar swing shaft 59. Yes. That is, as the lower shaft 37 rotates, the eccentric cam 61, the horizontal feed rod 49, the bell crank 48, the horizontal feed shaft 39, the transmission arm 33, the link member 32, the needle bar swing rod 59, the needle bar swing shaft 10 and A horizontal swing force is transmitted to the needle bar 13 via the needle bar swing base 11. The horizontal feed shaft 39 has its reciprocating rotation angle and phase adjusted by a feed amount adjusting mechanism 51 described later. When the reciprocating rotation angle and phase of the horizontal feed shaft 39 are adjusted by the feed amount adjusting mechanism 51, the swing angle amount and phase of the needle bar 13 are also adjusted at the same time, depending on the rotation amount of the horizontal feed shaft 39. The sewing product is fed in the forward direction or the reverse direction with a horizontal movement amount, that is, a feed pitch.

  Further, since the feed dog 44 is a needle feed sewing machine, as shown in FIG. 2, a needle hole 44a penetrating vertically is formed in the central portion thereof, and the sewing needle 13 is fed into the needle hole 44a when cloth is fed. The movement in the feeding direction is performed in the state inserted in.

[Feed adjustment mechanism]
As shown in FIGS. 1 and 2, a feed amount conversion body 52 having a groove portion 53 that is rotatably supported by the sewing machine frame 2 and extends in a direction orthogonal to the rotation center line direction inside the sewing machine bed 50. Is provided. One end of a bell crank 48 is slidably connected to the groove 53 of the feed amount converter 52 via a square piece 54 along the longitudinal direction of the groove 53 (see FIG. 3).
FIG. 5 is an exploded perspective view showing the relationship between the feed amount conversion body 52 and the feed adjustment motor 4. As shown in FIG. 5, the feed amount conversion body 52 is connected to the feed adjustment motor 4 via an arm member 56, a link member 57 and a swing shaft 58.
Here, when the feed amount conversion body 52 rotates, the groove portion 53 also rotates, so that the amount of movement of one end of the bell crank 48 in the horizontal direction changes via the square piece 54. Specifically, the movement amount of the bell crank 48 in the horizontal direction increases when the groove 53 is close to the horizontal, and the movement amount in the horizontal direction decreases when the groove 53 is close to the vertical (see FIG. 4). That is, the feed amount by the feed dog 44 (feed pitch) can be adjusted by rotating the feed amount conversion body 52 by driving the feed adjustment motor 4. Further, when the feed amount converter 52 is further rotated from the position where the feed amount becomes 0, the phase is reversed and transmitted, and the feed direction can be converted to the reverse direction. Also in this case, the feed amount in the reverse direction can be adjusted by further rotating.
Further, in this embodiment, the cloth feed mechanism and the needle feed mechanism are interlocked with each other, and these mechanisms cooperate to perform the needle feed. Therefore, the feed amount of the cloth feed mechanism 30 is adjusted by the feed amount adjustment mechanism 51. At this time, the needle swinging amount is also adjusted simultaneously via the needle bar swinging rod 59.

[Hook mechanism]
The hook mechanism 80 meshes with the horizontal hook 81 disposed below the feed dog 44, the main bevel gear 82 fixedly mounted on the lower shaft 37, the main bevel gear 82, and torques the horizontal hook via the hook shaft. And a driven bevel gear 83 that transmits From the main bevel gear 82 to the driven bevel gear 83, the rotation is increased at a double speed, and the rotation is imparted. As a result, the horizontal hook 81 rotates twice the vertical movement frequency of the sewing needle 13. Yes.

[Thread trimming device]
FIG. 6 is a perspective view of the thread trimming device 70. The thread trimming device 70 is a moving knife that captures an upper thread and a lower thread by reciprocating the tip part along the cloth feeding direction F by rotation in an area between a needle plate (not shown) and the horizontal hook 81. 71, a fixed knife 72 that cuts an upper thread and a lower thread by cooperating with the moving knife 71 by waiting at a predetermined position on the return path side of the moving knife 71 that performs reciprocating movement, and an outer periphery fixed to the lower shaft 37 A cam 73 having a cam groove formed on the surface thereof, a cam roller 74 that can be fitted into the cam groove, a transmission shaft 75 that holds the cam roller 74 and is given a turning action by the cam groove, and the cam roller 74 in the cam groove. And a thread trimming solenoid 76 for guiding the thread.
When the thread trimming solenoid 76 is actuated, the cam roller 74 enters the groove from the entrance of the cam groove at a predetermined upper shaft angle, and gives a reciprocating rotation operation to the moving knife 71 via the transmission shaft 75 according to the shape of the cam groove. And after thread trimming is complete, it is discharged from the exit of the cam groove.

In FIG. 6, a straight line N indicates an extension line of the needle bar and the sewing needle 13 when the needle bar 12 is positioned at the center of rotation where the needle bar 12 is vertical.
In the thread trimming device 70 described above, the cutting position at which the moving knife 71 performs thread trimming in cooperation with the fixed knife 72 is the extension line N and the maximum needle swing width that can be set around the extension line N. Is set to be downstream in the positive cloth feed direction F with respect to the entire range reached by the sewing needle when performing.

[Sewing machine control system]
The control system of the sewing machine 1 is shown in the block diagram of FIG. As shown in FIG. 7, the sewing machine 1 includes a control device 90 that controls the operation of each component. The control device 90 stores a program that controls the operation of the corners of the sewing machine 1 and other initial data. ROM 92, CPU 91 for executing a program in ROM 92, RAM 93 serving as a data storage area in the processing of CPU 91, and EEPROM 94 for storing various setting data requiring rewriting.

The control device 90 is connected to the sewing machine motor 60 via a motor drive circuit 60a for controlling the rotational speed of the sewing machine motor 60 and the like. The sewing machine motor 60 is provided with an encoder 62 for detecting the rotation angle thereof, and the control device 90 detects the upper shaft 9 from the output of the encoder 62.
The control device 90 is connected to the adjusting motor 4 and the thread trimming solenoid 76 via drive circuits 4a and 76a for controlling the respective operations.
Further, an input device for setting input such as a sewing pitch and displaying predetermined information, an operation panel 95 having a display screen, and a pedal 96 for instructing operation of the sewing machine 1 are connected to the control device 90 via an interface 97. ing.
The pedal 96 starts sewing when the front pedal is depressed, stops when the pedal is released, and inputs a thread trimming instruction when the rear pedal is depressed.

Next, setting of the sewing pitch will be described.
The sewing pitch input from the operation panel 95 is set to a range from a lower limit value Pmin to an upper limit value Pmax for the normal feed pitch width and the reverse feed direction as normal sewing pitch widths (for example, The lower limit value Pmin in the setting range is 2.5 [mm] and the upper limit value Pmax in the setting range is 9 [mm]), and the setting can be made in units of 0.5 [mm] within the range. The upper limit value in the set range is a maximum range that is a limit on the mechanism structure for preventing interference between the sewing needle 13 where the needle swing is performed and the moving knife 71 fixed knife 72 and the like.
In addition to normal sewing, there are sewing machines that can perform sewing called condensation sewing. The feed pitch of this condensation sewing is the lower limit (2.5 [mm] in the normal sewing setting range input from the operation panel 95. ]), Which is a smaller condensation stitching pitch Pco (for example, 1 [mm]). That is, in this sewing machine, the “maximum pitch adjustable by the feed amount adjusting mechanism” is 9 [mm], and the “minimum pitch adjustable by the feed amount adjusting mechanism” is 1 [mm].
When setting, select either normal feed or condensation stitching, and for normal stitching, select a value set in units of 0.5 [mm] in the range of 2.5 to 9 [mm], and change the feed direction. Set forward and reverse. When condensed sewing is selected, the pitch Pco (1 [mm]) is automatically determined and the forward / reverse setting of the feed direction is performed.
In this application, a sewing machine having a function of condensation sewing will be described as an example. However, for example, in the case of a sewing machine having no function of condensation sewing, setting of a normal sewing pitch width that can be set by an operation panel or the like. The lower limit of the range may be the “minimum pitch that can be adjusted by the feed amount adjustment mechanism”, or it may deviate from the normal sewing pitch width setting range and set a dedicated pitch width for smaller thread cutting. It is good also as "the minimum pitch which can be adjusted with a quantity adjustment mechanism."
A table showing the correspondence between the value of the feed pitch set and inputted from the operation panel 95 and the operation amount of the adjusting motor 4 for positioning the feed amount converter 52 at the rotation angle for obtaining the feed pitch is a ROM 92. The amount of operation of the adjusting motor 4 is determined according to the selected pitch.

[Operation control of sewing and thread trimming]
The operation control of the sewing machine 1 by the control device 90 will be described with reference to the flowchart of FIG. 8, the operation explanatory diagrams of FIGS. 9 and 10, and the explanatory view showing the position change of the feed dog 44 of FIG. 11. In FIG. 11, the horizontal axis indicates the upper axis angle, the vertical axis indicates the position of the feed dog in the sewing direction, and the 0 position on the vertical axis indicates the origin position of the feed dog 44 (the position at the upper axis angle of 0 °. Needle bar The top dead center is 0 ° of the upper axis angle), and the position above the zero position on the vertical axis is upstream of the origin position in the positive feed direction (left side in FIGS. 9 and 10), and the zero position on the vertical axis. The position below is the position downstream in the positive feed direction from the origin position (the right side in FIGS. 9 and 10). In the case of this example, a case where the set pitch is set to 4 [mm] by normal feed in the forward direction is illustrated.
9 and 10, reference numeral 17 denotes a needle plate provided at a needle drop position on the upper surface of the sewing machine bed portion 50, and reference numeral C denotes a fabric as a sewing object. In these drawings, the moving knife 71 is not shown, and only the fixed knife 72 (cutting position) is shown.

When the pedal 96 is stepped forward, sewing operation control is started. First, the control device 90 reads the currently set sewing pitch (referred to as the set pitch), and the feed amount converter 52 is rotated by the adjustment motor 4 so that the set pitch is obtained (step S1).
Next, the driving of the sewing machine motor 60 is started, and sewing is performed by needle feed at a set pitch (step S3).

After that, the control device 90 monitors the signal input by stepping on the pedal 96 (step S5), and when the signal by the back stepping is detected, the control device 90 enters the monitoring state of the output of the encoder 62 (step S7). ).
When the output of the encoder 62 reaches the lower stop position (upper shaft angle 230 ° [needle bar top dead center is 0 °]) (see FIG. 9A [230 °]), the control device 90 The adjustment motor 4 is controlled to set the sewing pitch to the condensation sewing pitch Pco in the positive feed direction (see step S9, FIG. 11 [1]).

Usually, the feed dog 44 protrudes from the upper surface of the needle plate 17 in the range of 90 to 270 ° in the upper axis angle and feeds by contacting the lower surface of the fabric C. Therefore, when the upper shaft angle is 230 °, the fabric C is being conveyed at the set pitch (4 [mm]) until then, and when the set pitch is changed at this timing, the feed dog 44 is newly set. Only the movement corresponding to the condensation sewing pitch Pco, which is a set pitch, is performed (see [240 °] in FIG. 9B).
It should be noted that the needle drop position at this stage is the “final knot point” where the needle drop that forms the final knot in which the upper thread and the lower thread are intertwined (reference numeral TL in FIG. 9B). In this thread trimming control, another needle drop (final needle drop) is performed at the condensation sewing pitch Pco after the final knot point, but since the thread is trimmed under the fabric after the final needle drop, the knot is No seam is formed.

After setting the condensation sewing pitch Pco, the control device 90 sets the needle penetration position (upper shaft angle 180 °) which is the penetration state of the sewing needle 13 with respect to the fabric C due to the final needle drop which is the next needle drop. Waiting for arrival (step S11).
During this time, the fabric is fed at the condensation stitching pitch Pco, the feed dog 44 descends and leaves the fabric C (see [0 °] in FIG. 9C), and the drive of the sewing machine motor 60 is further advanced. Again, the feed dog 44 rises and contacts the fabric C (see FIG. 9D [90 °]).

When the sewing needle 13 pierces the fabric C (see FIG. 9 (E) [120 °]) and further reaches the bottom dead center (see FIG. 10 (F) [180 °]), the control device 90, the adjusting motor 4 switches the sewing pitch to the upper limit value Pmax (9 [mm]) which is the maximum pitch in the positive feed direction (see step S13, FIG. 11 [2]).
When the output of the encoder 62 reaches the lower stop position (upper shaft angle 230 °) (step S15), the thread trimmer solenoid 76 is actuated to push the cam roller 74 of the thread trimmer 70 into the cam groove of the cam 73 (step S15). S17, see FIG. 11 [3]). Thereby, the thread trimming device 70 starts the thread trimming operation. Thereafter, the rotational speed of the sewing machine motor 60 is reduced to a predetermined low speed state for the yarn cutting operation.

Then, after setting the maximum pitch Pmax in the positive feed direction, the control device 90 waits to reach the feed dog separation position (upper axis angle of 0 °) in which the feed dog 44 is separated from the fabric ( Step S19).
During this time, the feed dog 44 moves forward at the maximum pitch Pmax and is the needle drop position next to the final knot point TL up to the position closest to the cutting position by the fixed knife 72 within the range in which the feed dog 44 can be conveyed. The final needle drop position TC is conveyed (see FIG. 10G [270 °]).

Further, when the feed dog 44 descends and separates from the fabric C and the upper shaft angle reaches the feed dog separation position (0 °) (see FIG. 10 (H) [0 °]), the control device 90 controls the adjustment motor 4. Thus, the sewing pitch is switched to the upper limit value Pmax (9 [mm]) which is the maximum pitch in the reverse feed direction (see step S21, FIG. 11 [4]).
As a result, the feed dog 44 that has moved in the direction away from the cutting position by the fixed knife 72 reverses its moving direction and starts to return to the cutting position by the fixed knife 72 again.
At an upper shaft angle of 50 °, the thread trimmer 70 carries the upper thread and lower thread extending downward from the needle hole 44a of the feed dog 44 to the cutting position by the fixed knife 72 and performs cutting (step S23, FIG. 10 ( J) See [50 °]).
Then, the drive of the sewing machine motor 60 is stopped, and the operation from sewing to thread trimming is completed.

[Technical effects of the embodiment]
As described above, after the needle drop after the final knot point TL (final needle drop) is performed at the condensed sewing pitch Pco by the sewing / thread trimming operation control of the control device 90, the final needle drop position TC is By the upper limit value Pmax which is the maximum pitch in the positive cloth feeding direction, the cutting position by the fixed knife 72 is maximized.
Further, the feed dog 44 is returned to the cutting position by the fixed knife 72 at the upper limit value Pmax which is the maximum pitch in the reverse cloth feed direction immediately before the thread trimming.

As a result, the upper thread is cut along the path that is the final knot point TL → the final needle drop position TC → the needle hole 44a of the feed dog 44 → the cutting position by the fixed knife 72, and the lower thread is the final knot point TL → feed. The tooth 44 is cut along a path that becomes a cutting position by the needle hole 44 a → the fixed knife 72.
(1) The distance between the final knot point TL and the final needle drop position TC is shortened by the condensation sewing pitch Pco which is the minimum pitch.
(2) The distance between the final needle drop position TC and the needle hole 44a of the feed dog 44 is close to each other and shortened by being brought close to the cutting position by the fixed knife 72 at the upper limit value Pmax which is the maximum pitch. It has become.
(3) The distance between the needle hole 44a of the feed dog 44 and the cutting position by the fixed knife 72 is close by the feed dog 44 being brought closer to the cutting position by the fixed knife 72 at the upper limit value Pmax which is the maximum pitch. It has been shortened.
(4) The distance between the final nodal point TL and the needle hole 44a of the feed dog 44 is shortened by bringing the feed dog 44 closer to the cutting position by the fixed knife 72 at the upper limit value Pmax which is the maximum pitch. .

For this reason, in the sewing machine that performs needle feeding, it is possible to shorten the remaining end length after cutting the upper thread and the lower thread to the maximum.
Further, since the final needle drop position TC and the feed dog 44 are both brought close to the cutting position by the fixed knife 72 at the upper limit value Pmax which is the maximum pitch, they are maximized regardless of the set sewing pitch during sewing. It is possible to approach the cutting position by the fixed knife 72, and it is possible to reduce the remaining end length after cutting the upper thread and the lower thread to the maximum regardless of the set sewing pitch during sewing.

[Other examples of sewing and thread trimming operation control]
In the above-described operation example, the case where the next stitch after the final knot point is fed with the condensation stitching pitch Pco in the positive feed direction is exemplified. However, the one stitch after the final knot point is fed with the condensation stitching pitch Pco in the reverse feed direction. It is possible to shorten the remaining ends of the upper thread and the lower thread even if it is fed by.
12 and 13 are explanatory diagrams of the operation in that case, and FIG. 14 is an explanatory diagram showing a change in the position of the feed dog 44. In the following, mainly the differences from the operation in the case where the one stitch next to the final knot will be fed at the condensation stitching pitch Pco in the positive feed direction will be mainly described.

Hereinafter, the operation is based on the control by the control device 90.
When a thread cutting instruction is input from the pedal, the sewing pitch is set to the condensed sewing pitch Pco in the reverse feed direction at the upper shaft angle of 230 ° (see FIG. 12A [230 °]). As a result, the position of the feed dog 44 first moves in the direction opposite to the cloth feed direction (see FIG. 14 [1]), so that the final node TL also moves in the reverse feed direction. It is fed in the reverse cloth feed direction at the condensation stitching pitch Pco (see FIG. 12B [240 °]).
Then, the feed dog 44 descends and leaves the fabric C (see FIG. 12C [0 °]), and the feed dog 44 rises again and contacts the fabric C (FIG. 12D [90 °]). reference).
When the sewing needle 13 pierces the fabric C (see FIG. 12E [120 °]), the final needle drop of the condensation sewing pitch Pco is formed downstream of the final knot point TL in the positive cloth feed direction. .
When the sewing needle 13 reaches the bottom dead center (see FIG. 13F [180 °]), the sewing pitch is set to the upper limit value Pmax (9 [mm]) which is the maximum pitch in the positive feed direction. The final needle drop position TC is conveyed to a position closest to the cutting position by the fixed knife 72 (see FIG. 13G [270 °]).
Further, when the feed dog 44 descends and separates from the fabric C and the upper shaft angle reaches the feed dog separation position (see FIG. 13 (H) [0 °]), the sewing pitch is the maximum pitch Pmax in the reverse feed direction ( 9 [mm]). As a result, the feed dog 44 reverses and returns to the cutting position side by the fixed knife 72, and the upper thread and the lower thread are cut at the upper shaft angle of 50 ° (see FIG. 13 (J) [50 °]).

Also in this example, (1) the distance between the final node TL and the final needle drop position TC, (2) the distance between the final needle drop position TC and the needle hole 44a of the feed dog 44, and (3) the feed dog 44, the distance between the needle hole 44a and the cutting position by the fixed knife 72, and (4) the distance between the final node TL and the needle hole 44a of the feed dog 44 are both shortened.
For this reason, in a sewing machine that performs needle feeding, the remaining end length after cutting of the upper thread and the lower thread can be shortened to the maximum, regardless of the set sewing pitch during sewing.

[Second Embodiment]
In the sewing machine 1 described above, the case where the thread cutting position by the moving knife 72 is set on the downstream side in the positive cloth feeding direction with respect to the rotation center position and the rotation range of the sewing needle 13 is exemplified. It is also possible to set the thread cutting position by 72 on the upstream side in the positive cloth feed direction with respect to the rotation center position and rotation range of the sewing needle 13.
FIGS. 15 and 16 are explanatory diagrams of the operation in that case, and FIG. 17 is an explanatory diagram showing a change in the position of the feed dog 44. These will be described.
Hereinafter, differences from the contents described in FIGS. 9 and 10 will be mainly described.

Hereinafter, the operation is based on the control by the control device 90.
In this example as well, a case where the set pitch is 4 [mm] in the normal feed in the forward direction is illustrated.
When a thread cutting instruction is input from the pedal, the sewing pitch is set to the condensed sewing pitch Pco in the reverse feed direction at the lower stop position (upper shaft angle 230 °) (see [230 °] in FIG. 15A). (See FIG. 17 [1]).
As a result, the position of the feed dog 44 first moves in the reverse cloth feed direction, so that the final knot point TL also moves in the reverse feed direction, and the final knot point TL is condensed by the feed dog 44 in the reverse cloth feed direction. It is sent at a pitch Pco (see FIG. 15B [240 °]).
Then, the feed dog 44 descends and leaves the fabric C (see FIG. 15C [0 °]), and the feed dog 44 rises again and contacts the fabric C (FIG. 15D [90 °]). reference).
When the sewing needle 13 pierces the fabric C (see FIG. 15E [120 °]), the final needle drop of the condensation sewing pitch Pco is formed downstream of the final knot point TL in the positive cloth feed direction. .
Further, when the sewing needle 13 reaches the bottom dead center (see FIG. 16F [180 °]), the sewing pitch is switched to the upper limit value Pmax (9 mm) which is the maximum pitch in the reverse feed direction (see FIG. 16). 17 [2]).
Then, at the lower stop position (upper shaft angle 230 °), the thread trimming solenoid 76 of the thread trimming device 70 operates (see FIG. 17 [3]).
On the other hand, the feed dog 44 moves in the reverse direction at an upper limit value Pmax that is the maximum pitch, and forms a seam at the final knot point up to a position closest to the cutting position by the fixed knife 72 within a range in which the feed dog 44 can be conveyed. The final needle drop position TC next to the needle drop is conveyed (see FIG. 16G [270 °]).
Further, the feed dog 44 descends and leaves the fabric C (see FIG. 16 (H) [0 °]), and when the upper shaft angle reaches the feed dog separation position (0 °) (FIG. 16 (H) [0 ° The sewing pitch is switched to the upper limit value Pmax (9 [mm]) which is the maximum pitch in the positive feed direction (see FIG. 17 [4]).
As a result, the feed dog 44 that has moved in the direction away from the cutting position by the fixed knife 72 reverses its moving direction and starts to return to the cutting position by the fixed knife 72 again.
Then, when the upper shaft angle is 50 °, the yarn cutting device 70 cuts the upper yarn and the lower yarn (see FIG. 16 (J) [50 °]).

Also in this example, (1) the distance between the final node TL and the final needle drop position TC, (2) the distance between the final needle drop position TC and the needle hole 44a of the feed dog 44, and (3) the feed dog 44, the distance between the needle hole 44a and the cutting position by the fixed knife 72, and (4) the distance between the final node TL and the needle hole 44a of the feed dog 44 are both shortened.
For this reason, in a sewing machine that performs needle feeding, the remaining end length after cutting of the upper thread and the lower thread can be shortened to the maximum, regardless of the set sewing pitch during sewing.
In the above example, the cloth feeding direction at the condensation sewing pitch Pco is the reverse cloth feeding direction, but the same applies when the cloth feeding direction at the condensation sewing pitch Pco is the positive cloth feeding direction. In addition, it is possible to shorten the remaining end length after cutting the upper thread and the lower thread to the maximum.

[Others]
In the above embodiment, a single-needle sewing machine has been exemplified. However, even in the case of a two-needle sewing machine, the thread trimming position by the fixed knife in the thread trimming device corresponding to each sewing needle is all relative to the sewing needle. When set to the downstream side in the positive cloth feeding direction, the remaining length of the sewing thread corresponding to each sewing needle is shortened by the control at the time of cutting shown in FIGS. 9 and 10 or 12 and 13. Is possible.
Similarly, in the needle feed sewing machine of the two-needle sewing machine, the thread trimming position by the fixed knife in the thread trimming device corresponding to each sewing needle is set upstream in the positive cloth feed direction with respect to the sewing needle. In this case, the remaining lengths of the sewing threads corresponding to the respective sewing needles can be shortened by the control at the time of cutting shown in FIGS.

[Other examples of feed adjustment mechanisms]
The feed adjustment mechanism is not limited to the above-described configuration, and may be configured as shown in FIGS.
The feed adjustment mechanism includes the feed amount conversion body 52, the arm member 56, and the link member 57 described above, and is connected to the link member 57 and fixedly supported by the lever shaft 501 along the Y-axis direction. A feed adjustment body 506 having a forward feed cam 504 and a reverse feed cam 505 that engage with a pin 503 held by the feed adjustment arm 502, and rotation of the feed amount conversion body 52 through the feed adjustment arm 502 and the feed adjustment body 506. A feed adjustment dial 507 that defines an angle, a feed adjustment body solenoid 508 that imparts rotation to the feed adjustment body 506 so as to have an upper limit value Pmax that is the maximum pitch, and a lever shaft 501 that switches from forward feed to reverse feed The reverse feed solenoid 509 for imparting rotation to the lever and the condensation for imparting rotation to the lever shaft 501 so that the condensation sewing pitch Pco is obtained. And solenoids 510, a manually mainly a lever 514 for switching the feeding direction of the grants rotated forward and backward to the lever shaft 501.

The feed adjusting arm 502 rotates together with the lever shaft 501, and the rotation moves the round bar-like pin 503 along the Y-axis direction around the lever shaft 501.
The feed adjusting body 506 is pivotally supported by the sewing machine frame so as to be rotatable about the Y axis, and its upper end is connected to the feed adjusting body solenoid 508 via a link 511.
In addition, a forward feed cam 504 and a reverse feed cam 505 are formed in the lower part of the feed adjustment body 506 so as to face each other and to be close to each other, as shown in FIG. The feed adjusting arm 502 is urged by an elastic body (not shown) so that the pin 503 comes into pressure contact with the forward feed cam 504.

The feed adjustment dial 507 has a tip abutting against the feed adjustment body 506 and can rotate the feed adjustment body 506 to an arbitrary angle by a dial operation.
When the feed adjusting body 506 rotates while the pin 503 is in pressure contact with the forward feed cam 504, the pressure contact position of the pin 503 changes along the forward feed cam 504, and the feed adjustment arm 502 also rotates. Further, the feed amount conversion body 52 rotates via the arm member 56 and the link member 57. Depending on which position of the forward feed cam 504 the pin 503 is in pressure contact with, the rotation angle of the feed amount conversion body 52 changes and the sewing pitch can be changed. That is, the sewing pitch can be arbitrarily adjusted by rotating the feed adjustment dial 507.

As described above, the forward feed cam 504 and the reverse feed cam 505 are formed so as to face each other and become narrower toward each other. The forward feed cam 504 and the reverse feed cam 505 are formed so that the sewing pitch decreases when the pin 503 moves in a direction where the mutual interval becomes narrower. Further, the forward feed cam 504 and the reverse feed cam 505 The sewing pitch is 0 when the pin 503 is located at the boundary position.
The aforementioned reverse feed solenoid 509 is connected to the lever shaft 501 via the link 512, and rotates the feed adjustment arm 502 against the elastic body, so that the pin 503 is connected to the reverse feed cam 505 as shown in FIG. Can be pressed.
When the feed adjuster 506 is stationary so as not to rotate, and the pin 503 moves from a state where it is pressed against the forward feed cam 504 to a state where it is pressed against the reverse feed cam 505, the pressure contact position with the original forward feed cam 504 The sewing pitch in the forward feed direction due to the above and the sewing pitch in the reverse feed direction due to the pressure contact position with the reverse feed cam 505 after the movement of the pin 503 are formed in a mutual cam shape so that the pitch widths coincide with each other. . In other words, when the pin 503 moves from a state where it is pressed against the forward feed cam 504 to a state where it is pressed against the reverse feed cam 505 by operating the reverse feed solenoid 509, only the feed direction can be switched between forward and reverse while maintaining the sewing pitch. It is possible.
The reverse feed solenoid 509 may have a configuration in which the stroke amount is adjusted so that the rotation of the adjustment arm 502 stops at a predetermined position. That is, the position where the rotation of the adjustment arm 502 by the reverse feed solenoid 510 rotates and stops the feed amount converter 52 via the arm member 56 and the link member 57 is the upper limit value Pmax which is the maximum pitch in the reverse feed direction. The configuration may be set so as to be.

  The condensation solenoid 510 is connected to the lever shaft 501 via the link 513 and rotates the feed adjusting arm 502 against the elastic body. The stroke of the condensation solenoid 510 is adjusted so that the rotation of the adjustment arm 502 stops at a predetermined position. That is, the position at which the rotation of the adjustment arm 502 by the condensation solenoid 510 rotates and stops the feed amount conversion body 52 via the arm member 56 and the link member 57 is the above-described normal feed or The condensation sewing pitch Pco in the reverse feed direction is set.

  The feed adjusting body solenoid 508 is connected to the feed adjusting body 506 via the link 511, and by rotating the feed adjusting body 506, as shown in FIG. Are relatively moved to a position where the maximum pitch P is the upper limit value Pmax.

With these configurations, the feed adjusting mechanism shown in FIG. 22 can execute any operation during the thread trimming of the sewing machine shown in FIGS.
For example, in the operation of FIG. 11, when switching from the normal sewing pitch preset by the feed adjustment dial 507 to the condensation sewing pitch Pco, the feed adjustment solenoid 508, the reverse feed solenoid 509, and the condensation solenoid 510 are Then, only the condensation solenoid 510 is operated from the state of zero thrust (the state of FIG. 19), and the state is switched to the state of FIG.
Further, in the operation of FIG. 11, when the sewing pitch is switched to the upper limit value Pmax as the maximum forward feed pitch, the condensation solenoid 510 and the reverse feed solenoid 509 are turned off, and the feed adjustment solenoid 508 is turned on. Switch to the state of FIG.
Further, in the operation of FIG. 11, when the sewing pitch is switched to the upper limit value Pmax as the maximum reverse feed pitch, the condensation solenoid 510 is turned off, the feed adjustment solenoid 508 and the reverse feed solenoid 509 are turned on. Switch to 20 state. (When the stroke amount of the reverse feed solenoid 509 is set in advance so as to be the upper limit value Pmax as the maximum reverse feed pitch, the reverse feed solenoid 509 is in the ON state, and the condensation solenoid 510 and the feed adjusting solenoid 510 are turned off. State)

Further, when the operation of FIG. 14 is executed, it is necessary to design the stop position of the pin 503 by the condensation solenoid 510 to be the condensation sewing pitch Pco in the reverse feed direction.
In this case, when switching from the normal sewing pitch preset by the feed adjustment dial 507 to the reverse feed condensation sewing pitch Pco, the feed adjuster solenoid 508, the reverse feed solenoid 509, and the condensation solenoid 510 are all used. Only the condensation solenoid 510 is operated from the state where the thrust is zero and the thrust is zero (the state shown in FIG. 19), and the position is switched to a predetermined position where the condensation sewing pitch Pco in the reverse feed direction is obtained.
Further, in the operation of FIG. 14, when the sewing pitch is switched to the upper limit value Pmax as the maximum forward feed pitch, the condensation solenoid 510 and the reverse feed solenoid 509 are turned off, and the feed adjustment solenoid 508 is turned on. Switch to the state of FIG.
Further, in the operation of FIG. 14, when the sewing pitch is switched to the upper limit value Pmax as the maximum reverse feed pitch, the condensation solenoid 510 is turned off, the feed adjustment solenoid 508 and the reverse feed solenoid 509 are turned on. Switch to 20 state. (When the stroke amount of the reverse feed solenoid 509 is set in advance so as to be the upper limit value Pmax as the maximum reverse feed pitch, the reverse feed solenoid 509 is in the ON state, and the condensation solenoid 510 and the feed adjusting body solenoid 508 are turned off. State)

Also, when the operation of FIG. 17 is executed, it is necessary to design the stop position of the pin 503 by the condensation solenoid 510 to be the condensation sewing pitch Pco in the reverse feed direction.
In this case, when switching from the normal sewing pitch preset by the feed adjustment dial 507 to the reverse feed condensation sewing pitch Pco, the feed adjustment solenoid 508, the reverse feed solenoid 509, and the condensation solenoid 510 are all used. Only the condensation solenoid 510 is operated from the state where the thrust is zero and the thrust is zero (the state shown in FIG. 19), and the position is switched to a predetermined position where the condensation sewing pitch Pco in the reverse feed direction is obtained.
Further, in the operation of FIG. 17, when the sewing pitch is switched to the upper limit value Pmax as the maximum reverse feed pitch, the condensation solenoid 510 is turned off, the feed adjustment solenoid 508 and the reverse feed solenoid 509 are turned on, Switch to 20 state. (When the stroke amount of the reverse feed solenoid 509 is set in advance so as to be the upper limit value Pmax as the maximum reverse feed pitch, the reverse feed solenoid 509 is in the ON state, and the condensation solenoid 510 and the feed adjusting body solenoid 508 are turned off. State)
Further, in the operation of FIG. 17, when switching the sewing pitch to the upper limit value Pmax as the maximum forward feed pitch, the condensation solenoid 510 and the reverse feed solenoid 509 are turned off, and the feed adjustment solenoid 508 is turned on. Switch to the state of FIG.

As described above, the feed adjusting mechanism shown in FIG. 18 needs to change the design of the stop position by the condensation solenoid 510, but can execute any of the operations shown in FIGS.
In FIG. 18, each of the solenoids 508, 509, 510 of the feed adjustment mechanism is a rotary solenoid. However, the present invention is not limited to this, and the solenoids 508, 509, 510 can be moved forward and backward in the longitudinal direction of the links 511, 512, 513. It is also possible to use a dynamic solenoid.

DESCRIPTION OF SYMBOLS 1 Needle feed sewing machine 2 Sewing machine frame 4 Adjustment motor 9 Upper shaft 12 Needle bar 13 Sewing needle 14 Needle feed mechanism 17 Needle plate 30 Cloth feed mechanism 44 Feed dog 44a Needle hole 51 Feed amount adjustment mechanism 52 Feed amount conversion body 60 Sewing motor 70 Thread trimmer 71 Moving knife 72 Fixed knife 80 Hook mechanism 90 Controller F Sewing direction

Claims (2)

An upper shaft that is rotationally driven by a sewing machine motor;
A needle bar vertical movement mechanism that moves the needle bar up and down in synchronization with the rotation of the upper shaft;
A needle feed mechanism that swings the needle bar along the cloth feed direction in synchronization with the rotation of the upper shaft;
Synchronously with the rotation of the upper shaft, a cloth feed mechanism for feeding the workpiece by rotating the feed dog in which the needle hole is formed in an elliptical locus along the cloth feed direction;
A thread trimming device for cutting the upper thread and the lower thread on the downstream side in the positive cloth feed direction with respect to the sewing needle supported by the needle bar;
A feed amount adjusting mechanism for adjusting the sewing pitch;
A control device for controlling the operation of the thread trimming device and the feed amount adjusting mechanism;
In the sewing machine that feeds the cloth by the feed dog in a state where the sewing needle is lowered and pierced by the workpiece,
The controller is
With the sewing needle forming the seam of the final knot point stuck in the workpiece, the feed pitch is set to the minimum pitch that can be adjusted by the feed amount adjusting mechanism in the forward or reverse cloth feed direction. Further, the feed pitch is set as the maximum pitch that can be adjusted by the feed amount adjustment mechanism in the positive cloth feed direction in a state in which the sewing needle that has made the needle drop next to the final knot is stuck in the workpiece. Feed the workpiece,
The feed pitch is set to the maximum pitch that can be adjusted by the feed amount adjusting mechanism in the reverse cloth feed direction until the feed dog that has been fed at the maximum pitch is separated from the sewing product until thread trimming is performed. A sewing machine that controls the feed amount adjusting mechanism so as to move the feed dog. An upper shaft that is rotationally driven by a sewing machine motor;
A needle bar vertical movement mechanism that moves the needle bar up and down in synchronization with the rotation of the upper shaft;
A needle feed mechanism that swings the needle bar along the cloth feed direction in synchronization with the rotation of the upper shaft;
Synchronously with the rotation of the upper shaft, a cloth feed mechanism for feeding the workpiece by rotating the feed dog in which the needle hole is formed in an elliptical locus along the cloth feed direction;
A thread trimming device that cuts the upper thread and the lower thread upstream of the sewing needle supported by the needle bar in the positive cloth feed direction;
A feed amount adjusting mechanism for adjusting the sewing pitch;
A control device for controlling the operation of the thread trimming device and the feed amount adjusting mechanism;
In the sewing machine that feeds the cloth by the feed dog in a state where the sewing needle is lowered and pierced by the workpiece,
The controller is
With the sewing needle forming the seam of the final knot point stuck in the workpiece, the feed pitch is set to the minimum pitch that can be adjusted by the feed amount adjusting mechanism in the forward or reverse cloth feed direction. In addition, the feed pitch is set to the maximum pitch that can be adjusted by the feed amount adjusting mechanism in the reverse cloth feed direction in a state where the sewing needle that has made the needle drop next to the final knot is stuck in the workpiece. Feed the workpiece,
The feed pitch is set to the maximum pitch that can be adjusted by the feed amount adjusting mechanism in the positive cloth feed direction until the feed dog that has been fed at the maximum pitch is separated from the sewing product until thread trimming is performed. A sewing machine that controls the feed amount adjusting mechanism so as to move the feed dog.

Images