JP4419643B2 - Upper thread clamping mechanism of sewing machine - Google Patents

Description

  The present invention relates to an upper thread clamping mechanism of a sewing machine, and in particular, when forming stitches for several stitches at the start of sewing, the thread end of the upper thread is clamped below the needle plate, and the stitch skipping at the start of sewing is performed. It relates to the thing which prevented it.

Conventionally, in various types of sewing machines such as a bar-tacking machine that forms a bar-tacking seam, at the start of sewing, depending on the type of work cloth and upper thread, the upper thread may come off from the eye of the sewing needle due to the lifting of the balance, Seams may not be formed. Therefore, at the start of sewing, the needle end of the upper thread remaining on the lower side of the needle plate when the sewing needle descends through the needle hole from the uppermost position and moves to the upper side of the needle plate during the next upward movement. the part, as previously nipped to several stitch is formed, the upper thread holding device of a sewing machine which is adapted to prevent contact Keru skipped stitches at sewing start have been proposed.

  For example, an upper thread clamp device of a sewing machine described in Japanese Patent No. 2671478 is provided with a support block, a guide bar, an air cylinder, etc. on the lower side of a needle plate, and the thread clamp is aligned with the needle hole at the start of sewing. When the sewing machine moves to the first movement position and the sewing needle of the first stitch moves to the upper side of the needle plate, the thread clamp moves from the first movement position to the second movement position, and the thread end cooperates with the lower surface under the needle. When a predetermined number of stitches (for example, 2 stitches) are sewn, the thread clamp rotates and the thread retainer moves downward to release the upper end. (For example, refer to Patent Document 1).

Japanese Patent No. 2671478 (pages 2 and 3, FIG. 1)

  In the upper thread clamp device of the sewing machine described in the above-mentioned Japanese Patent No. 2671478, a plurality of air cylinders, support blocks, guide bars, etc. Since the upper thread gripping device is configured by providing a plurality of members, the upper thread gripping device is complicated and enlarged, so that the bed portion is enlarged and the manufacturing cost is increased and the weight cannot be reduced. There is a problem such as that.

An upper thread clamping mechanism of a sewing machine according to claim 1 is a needle thread clamping mechanism for a sewing machine that releasably clamps the thread end portion of the upper thread extending from the stitch hole of the sewing needle below the needle plate of the bed portion. The first thread holding member pivotally attached to the lower surface of the needle plate by a vertical pin member, and a thread hole that allows a sewing needle to pass through the needle hole of the needle plate, and cooperates with the first thread holding member. And a second thread clamping member that is pivotally attached to a needle plate by a vertical pin member, and a second thread clamping member. For rotationally driving a start position that matches the needle hole of the needle plate, a clamping position that clamps the thread end in cooperation with the first thread clamping member, and a release position that releases the clamping of the thread end. and a rotation driving means, when a second Itokyoji member rotates to the release position from the gripping position, the first Itokyoji member, second Itokyoji member and co And the holding position for holding the yarn end to, those that are configured to be rotatable over a release position for releasing the holding of the yarn end.

  Since the first thread clamping member is attached to the lower surface of the needle plate and the second thread clamping member is pivotally attached to the needle plate by a vertical pin member, the second thread clamping member is at the start position. At a certain time, the thread hole of the second thread clamping member and the needle hole of the needle plate coincide with each other, so that the sewing needle can pass and sewing is started. When the first sewing needle after the start moves to the upper side of the needle plate, the second thread clamping member is rotated to the clamping position by the rotation driving means, so that the thread end portion cooperates with the first thread clamping member. Is pinched. When the sewing for several stitches is executed, the second thread clamping member is rotated to the release position by the rotation driving means, so that the thread end portion is released. Therefore, there is no skipping at the start of sewing.

Further, since the first Itokyoji member is rotatably pivoted to the needle plate by a vertical pin members, in cooperation with the first Itokyoji member during rotation of the clamping position of the second Itokyoji member The yarn end is clamped, and when the second yarn clamping member is rotated to the release position, the first yarn clamping member is also rotated to the release position to release the yarn end from being clamped.

The upper thread clamping mechanism of the sewing machine according to claim 2 is the invention according to claim 1, wherein the clamping position relative to the start position is a position where the second thread clamping member is rotated by a first angle, The release position is a position where the second thread clamping member is rotated by the second angle in the same direction as the first angle. In this case, the second thread clamping member rotates from the starting position to the clamping position by the rotation of the first angle, and further rotates from the clamping position to the release position by the rotation of the second angle in the same direction. Since the thread end portions at the clamping position and the release position are located to the side of the position of the sewing needle, the thread end portions are not sewn during sewing when the thread end portion is clamped.

An upper thread clamping mechanism of a sewing machine according to a third aspect is the invention according to the second aspect , wherein the elastic member that biases the first thread clamping member toward the clamping position and the biasing force of the elastic member to the first thread clamping member. And a locking member that locks against the clamping position. In this case, since the rotation of the first thread clamping member to a position other than the clamping position is suppressed by the urging force of the elastic member, the second thread clamping member rotated to the clamping position and the first position held at the clamping position are held. A yarn end is clamped with one yarn clamping member.

The upper thread clamping mechanism of the sewing machine according to claim 4 is the invention according to claim 2 or 3 , wherein the rotation fulcrum of the first thread clamping member is provided on the base side in the length direction of the bed from the needle hole. The rotation fulcrum of the two-thread clamping member is provided further on the root side than the rotation fulcrum of the first thread clamping member. In this case, when the second thread clamping member is rotated to the clamping position, the clamping part of the second thread clamping member and the clamping part of the first thread clamping member located at the clamping position overlap with each other. The part is pinched. However, when the second yarn clamping member is rotated to the clamping position, the two nip portions are displaced due to the difference of the rotation fulcrum, and the yarn hole of the second yarn clamping member is opened. The clamping of the part is released.

The upper thread clamping mechanism of the sewing machine according to claim 5 is the invention according to any one of claims 1 to 4 , wherein the rotation driving means includes an electric actuator and a link mechanism that connects the electric actuator to the second thread clamping member. The connection between the second thread holding member and the connecting member in the link mechanism is configured to be released as the needle plate and the second thread holding member are removed from the bed portion. . In this case, when the needle plate and the second thread clamping member pivotally attached to the needle plate via the pin member are removed from the bed, the connection between the second thread clamping member and the connecting member is released, and the needle plate is It can be removed with the first and second thread clamping members attached.

The upper thread clamping mechanism of the sewing machine according to a sixth aspect is the invention according to the fifth aspect , wherein the connecting portion of the second thread clamping member is disposed on the upper side of the connecting portion of the connecting member and is located on the lower side. An upward connection pin is provided in the connection portion, and an engagement hole that can be engaged with the connection pin is formed in the connection portion of the second thread clamping member located on the upper side. In this case, only lift the needle plate, the engagement hole of the connecting portion of the second Itokyoji member disposed on the upper side, connection is provided upward on the connecting portion of the connecting member disposed on the lower side pin Therefore, the needle plate can be removed with the first and second thread clamping members attached thereto.

The upper thread clamping mechanism of the sewing machine according to claim 7 is the sewing machine according to claim 5 , wherein the origin position of the second thread clamping member accompanying the initial setting of the electric actuator is set to the start position. In this case, when the initial setting of the electric actuator is executed, the second thread clamping member rotates to the starting position which is the origin position. Therefore, even if the sewing is started immediately at the starting position, the sewing needle and the second thread clamping are There is no interference with the member.

Expanding the upper thread clamping mechanism of sewing machine according to claim 8, in any one of the claims 1 to 7, the moving side of the first Itokyoji member at the distal end having a thread hole of the second Itokyoji member And a part of the enlarged portion is superposed on the first thread clamping member at least at the start position of the second thread clamping member. In this case, since the enlarged portion formed on the moving side of the tip portion having the thread hole of the second yarn clamping member to the first yarn clamping member is superposed on the first yarn clamping member at least at the start position, When the second thread clamping member rotates to the clamping position, the second thread clamping member can smoothly move while maintaining a predetermined moving speed without colliding with the first thread clamping member through overlapping with the first thread clamping member of the enlarged portion. Move to the clamping position.

According to a ninth aspect of the present invention, the upper thread clamping mechanism of the sewing machine according to any one of the first to eighth aspects further comprises a first detection sensor for detecting that the second thread clamping member is at a start position. . In this case, the first detection sensor detects that the second thread clamping member has rotated to the start position.

Upper thread clamping mechanism of sewing machine according to claim 1 0, in the invention of claim 9, in which said second Itokyoji member is provided with second detection sensor which detects that it is in the release position. In this case, the second detection sensor detects that the second thread clamping member has rotated to the release position.

  According to the first aspect of the present invention, since the first thread clamping member, the second thread clamping member, and the rotation driving means are provided, the second thread clamping member is rotated to the start position by the rotation driving means. Sewing starts, and when the first sewing needle after the start moves to the upper side of the needle plate, the second thread clamping member is rotated to the clamping position, so that the second thread clamping member and the first thread The yarn end can be securely clamped in cooperation with the clamping member.

  On the other hand, when the sewing for several stitches is executed, the second thread clamping member is rotated to the release position and the thread end is released, so that skipping at the start of sewing can be reliably prevented. it can. In addition, since the second thread clamping member is merely rotated from the start position to the clamping position, and further from the clamping position to the release position, the configuration of the upper thread clamping mechanism can be simplified, the sewing machine can be reduced in size and weight, and further reduced. Cost can be reduced.

The first Itokyoji member is pivoted rotatably by the vertical of the pin member to the lower surface of the needle plate, when a second Itokyoji member rotates to the release position from the gripping position, the second Itokyoji member Since it is configured to be able to rotate between a holding position for holding the yarn end portion in cooperation with the release position for releasing the holding of the yarn end portion, the second yarn holding member is moved to the holding position when it is turned. The yarn end can be pinched in cooperation with the one yarn holding member, and the first yarn holding member is also turned to the release position when the second yarn holding member is turned to the release position. It can be canceled .

According to a second aspect of the present invention, the clamping position is at a position where the second thread clamping member is rotated by a first angle with respect to the start position, and the release position is at the first thread clamping member with respect to the clamping position. Since the thread end portion at the clamping position or the release position is located at the side of the position of the sewing needle by the first angle or the second angle because it is at the position rotated by the second angle in the same direction as the angle. The thread end portion is not sewn during sewing with the thread end portion clamped. Other effects similar to those of the first aspect are obtained .

According to invention of Claim 3 , the elastic member which urges | biases the said 1st thread | yarn clamping member toward the clamping position, and the engagement which latches the 1st thread | yarn clamping member in the clamping position against the urging | biasing force of an elastic member. Since the stop member is provided, the first thread clamping member is restrained from rotating to a position other than the clamping position by the urging force of the elastic member. Therefore, the first thread clamping member is positioned at the clamping position and the second thread clamping member rotated to the clamping position. The yarn end portion can be securely held by the held first yarn holding member. Other effects similar to those of the second aspect are achieved.

According to a fourth aspect of the present invention, the rotation fulcrum of the first thread clamping member is provided on the base side in the length direction of the bed from the needle hole, and the rotation fulcrum of the second thread clamping member is the first thread clamping Since it is provided further on the base side than the rotation fulcrum of the member, the clamping part of the second thread clamping member rotated to the clamping position overlaps with the clamping part of the first thread clamping member already located at the clamping position, While the end of the yarn can be securely held by these holding portions, when the second yarn holding member is rotated to the holding position, the two holding portions are displaced due to the difference in the rotation fulcrum. The opening of the thread hole of the member can surely release the end of the thread end. Other effects similar to those of any one of claims 1 to 3 are achieved.

According to the invention of claim 5, the rotation driving means includes an electric actuator and a link mechanism that connects the electric actuator to the second thread clamping member, and the connection that the second thread clamping member and the link mechanism have. Since the connection with the member is configured to be released as the needle plate and the second thread holding member are removed from the bed portion, when the needle plate is removed from the bed portion, the second thread holding member and the connecting member Since the connection is released, the needle plate can be easily removed with the first and second thread clamping members attached thereto. Other effects similar to those of any one of claims 1 to 4 can be achieved.

According to invention of Claim 6 , the connection part of the said 2nd thread clamping member is arrange | positioned above the connection part of the said connection member, an upward connection pin is provided in the connection part of the connection member located below, and upper side Since the engaging hole that can be engaged with the connecting pin is formed in the connecting portion of the second thread holding member located at the position of the second thread holding member, the engaging portion of the connecting portion of the second thread holding member disposed on the upper side can be simply lifted up. Since the connecting pin of the connecting portion of the connecting member disposed on the lower side is removed from the joint hole, the needle plate can be easily removed with the first and second thread clamping members attached thereto. Other effects similar to those of the fifth aspect are obtained.

According to the seventh aspect of the present invention, since the origin position of the second thread clamping member associated with the initial setting of the electric actuator is set to the start position, the second thread clamping is performed when the initial setting of the electric actuator is executed. Since the member rotates to the start position which is the origin position, the sewing can be started immediately at the start position, and interference between the sewing needle and the second thread clamping member can be reliably prevented. Other effects similar to those of the fifth aspect are obtained.

According to the invention of claim 8 , the enlarged portion is formed on the moving side to the first yarn clamping member at the tip portion having the yarn hole of the second yarn clamping member, and enlarged at least at the start position of the second yarn clamping member. Since a part of the portion is overlapped with the first thread clamping member, when the second thread clamping member rotates to the clamping position, the first thread clamping member overlaps with the first thread clamping member through the first thread clamping member. While maintaining a predetermined movement speed without colliding with the yarn clamping member, smooth movement to the clamping position can be realized, and the clamping operation can be speeded up. Other effects similar to those of any one of claims 1 to 7 can be achieved.

According to the ninth aspect of the present invention, since the first detection sensor for detecting that the second thread clamping member is at the start position is provided, the first detection sensor rotates the second thread clamping member to the start position. Can be reliably detected, and the detection signal from the first detection sensor can be effectively utilized for the upper thread clamping control at the start of sewing. Other effects similar to those of any one of claims 1 to 8 can be achieved.

According to the invention of claim 1 0, since the second Itokyoji member is provided with second detection sensor which detects that it is in the release position, rotating to the release position of the second Itokyoji member by the second detection sensor The movement can be reliably detected, and the detection signal from the second detection sensor can be effectively used for the upper thread clamping control at the start of sewing. Other effects similar to those of the ninth aspect are achieved.

  The upper thread clamping mechanism of the sewing machine in the present embodiment includes a first thread clamping plate having a first thread clamping part and a second thread clamping plate having a second thread clamping part and a thread hole on the lower surface of the bed part, respectively. The second thread clamping plate is pivotally mounted, and the second thread clamping plate is clamped by the thread clamping motor, and the thread end is clamped in cooperation with the start position where the thread hole matches the needle hole of the needle plate and the first thread clamping plate. It is made to drive rotationally to a clamping position and a release position for releasing the clamping of the yarn end.

  As shown in FIG. 1, the electronic tacking sewing machine 1 is placed on a work table 8, and includes a bed portion 2, a pedestal portion 5 erected upward from a rear end portion of the bed portion 2, and a pedestal portion. 5 is composed of an arm portion 6 that extends forward from the upper end of 5 so as to face the bed portion 2.

  An operation panel 9 (see FIG. 10) is provided on the work table 8. The operation panel 9 includes a liquid crystal display, a selection switch for selecting the type of stitches to be used for sewing and a stitch pattern, and an upper thread. There are provided various types of switches and lamps for setting various sewing conditions such as a thread holding mode switch for setting whether or not to hold the end of the thread, sewing speed, and the like.

  A sewing machine motor 67 (see FIG. 10) for driving the sewing needle 11 up and down through the needle bar 10 and the driving force of the sewing machine motor 67 are transmitted to the sewing needle 11 through the main shaft. A driving force transmission mechanism, a presser drive mechanism (not shown) that moves the presser foot 13 up and down via a presser foot mechanism (not shown), and the like are provided, and the needle bar 10 is moved up and down inside the front end portion of the arm portion 6. A needle bar up-and-down moving mechanism to be moved, a balance driving mechanism for driving a balance for pulling up the upper thread, and the like are provided.

  The bed portion 2 includes a bed main body portion 3 on which a pedestal column portion 5 is erected and a cylinder bed portion 4 extending forward from the bed main body portion 3, and a needle plate having a needle hole 12 a on the upper surface of the cylinder bed portion 4. 12 is detachably fixed.

  Although not shown in the figure, the bed 2 includes a cloth presser mechanism having a presser foot 13 and a cloth feed mechanism for moving the needle plate 12 and the feed plate 14 in the front-rear direction (Y direction) and the left-right direction (X direction). Thus, a vertical hook (half-turn hook) 15 that forms a tack-stopped seam in time with the vertical movement of the sewing needle 11, a lower shaft 16 that transmits a half-rotation driving force to the vertical hook 15, and an upper thread clamping described later A mechanism 20 and a thread trimming mechanism (not shown) for cutting the upper thread and the lower thread at the end of sewing are provided.

  As shown in FIG. 3, the vertical hook 15 is arranged in a front-facing manner, and a vertical hook 15a attached to the sewing machine frame, a rotary hook 15b rotatably supported by the big hook 15a, The driver 15c is composed of a driver 15c and the like, and the driver 15c is driven by the lower shaft 16 by half rotation. A bobbin case 17 is accommodated in the inner hook 15b, and a sword tip 15d is formed.

  Here, a foot pedal 18 (see FIG. 10) is provided on the lower side of the work table 8, and when the operator depresses to the first presser position, the presser motor 68 is driven through the presser foot mechanism. Sewing control is started when the presser foot 13 is lowered from the raised position to the lowered position (pressed position) on the top surface of the needle plate 12 and is depressed to the second stage sewing position by the operator.

  Next, the upper thread clamping mechanism 20 provided in the bed part 2 will be described. The upper thread clamping mechanism 20 includes a first thread clamping plate 21 (which corresponds to the first thread clamping member) pivoted on the lower surface of the needle plate 12 and a second thread clamping plate 22 (which corresponds to the second thread clamping member). And a rotation driving mechanism 35 (which corresponds to the rotation driving means) for driving the first and second thread clamping plates 21 and 22 to rotate.

  As shown in FIGS. 2 to 5, on the lower surface of the needle plate 12, the proximal end portion of the substantially L-shaped first thread clamping plate 21 is vertically rearward and leftward from the needle hole 12 a. A pin 23 (which corresponds to a pin member) is pivotally mounted so as to be rotatable. A first thread clamping portion 21b is formed at the front end of the clamping arm portion 21a of the first thread clamping plate 21, and a stopper portion 21d (this corresponds to a locking member) on the spring receiving portion 21c of the first thread clamping plate 21. ) Are integrally formed so as to protrude rearward.

  Further, on the lower surface of the needle plate 12, the base end portion of the substantially L-shaped second thread clamping plate 22 is located behind the needle hole 12a and behind the pivot point of the first thread clamping plate 21 (the bed). At the base side in the length direction of the portion 2, it is pivotally attached by a vertical second pivot pin 24 (which corresponds to a pin member). That is, the first thread clamping plate 21 is disposed on the lower surface of the needle plate 12, and the second thread clamping plate 22 is disposed immediately below the first thread clamping plate 21.

  A thread hole 22b that allows the sewing needle 11 and the upper thread 7 to pass therethrough is formed at the distal end of the gripping arm part 22a of the second thread clamping plate 22, and the second thread clamping part 22c is formed at the front end portion adjacent to the thread hole 22b. Is formed. An enlarged portion 22g is formed on the moving side (left side) to the first yarn clamping plate 21 in the second yarn clamping portion 22c in which the yarn hole 22b is formed. As shown in FIG. 4, even when the second yarn clamping portion 22c is located at the start position 22 (S), a part of the enlarged portion 22g of the first yarn clamping plate 21 is not shown in FIG. It superposes | stacks on the 1st thread clamping part 21b from the lower side.

  A spring locking plate 25 is fixed to the rear end portion of the needle plate 12, and a tension coil spring 26 is hung between the spring locking plate 25 and the tip of the spring receiving portion 21c of the first thread clamping plate 21. Yes. Therefore, the first thread clamping plate 21 is elastically biased counterclockwise in a plan view by the spring force of the tension coil spring 26, that is, toward the clamping position 21 (K), but the stopper portion 21d is Abutting on an upward boss portion 22d formed at the base end portion of the second thread clamping plate 22 is locked at a clamping position 21 (K) shown in FIG.

  Here, the connecting portion of the connecting arm portion 22e of the second thread clamping plate 22 is disposed on the upper side of the connecting portion, which is the tip of a thread clamping linkage 45 of the rotation drive mechanism 35 described later, and is located on the upper side. An engagement hole 22f is formed in the connecting portion of the two-thread holding plate 22, and an upward connecting pin 46 is fixed to the connecting portion of the thread-holding linkage 45 located on the lower side. Therefore, the coupling pin 46 is fitted into the engagement hole 22f so that the connection can be released from the lower side, and the second thread clamping plate 22 and the thread clamping linkage 45 engage the coupling pin 46 and the engagement hole 22f. It is connected so that rotation is possible.

  Furthermore, the engagement pin 27 is fixed to the upper surface from the rear side of the thread hole 22b of the clamping arm portion 22a of the second thread clamping plate 22, and the second thread clamping plate 22 is held at the clamping position 22 (K) shown in FIG. 8 to the release position (L) shown in FIG. 8, the engaging pin 27 engages with the clamping arm portion 21 a of the first thread clamping plate 21, and the first thread clamping plate 21 is pulled by the tension coil spring 26. Against this spring force, it rotates from the clamping position 21 (K) shown in FIG. 6 to the release position 21 (L) shown in FIG.

Here, a fixed blade 30 having a blade portion is screwed to the lower surface of the needle plate 12, and a movable blade 31 having a blade portion is pivotally attached by a pivot pin 32. The movable blade 31 is connected to the distal end of the thread cutting continuous rod 33, during thread cutting, since the thread cutting continuous rod 3 3 via a thread cutting drive system by driving the thread cutting solenoid 69 is moved forward, the movable blade 31 The upper thread 7 and the lower thread are cut in cooperation with the fixed blade 30 and the details thereof are omitted.

  Next, the second thread clamping plate 22 is rotated through the thread clamping linkage 45 over the start position 22 (S), the clamping position 22 (K), and the release position 22 (L). The drive mechanism 35 is demonstrated based on FIG.1, FIG.2, FIG.4.

  A thread clamping motor 36 composed of a stepping motor is disposed downward on the bed main body 3 and is fixed to the frame via an attachment plate 37. The base end portion of the drive lever 38 is fixed to the drive shaft 36 a of the yarn clamping motor 36, and the base end portion of the L-shaped link plate 39 is connected to the tip end portion of the drive lever 38 by a connecting bolt 40. A rotation lever 41 having upper and lower connecting arm portions 41a and 41b is disposed on the side of the thread clamping motor 36, and is pivotally supported on the frame via a vertically-supported pivot shaft 42.

  The other end portion of the link plate 39 is connected to the lower connecting arm portion 41a of the rotating lever 41 by a connecting bolt 43, and one end portion of the thread clamping linkage 45 is connected to the upper connecting arm portion 41b of the rotating lever 41. They are connected by connecting bolts 44. A connecting pin 46 fixed to the upper surface of the tip end portion of the yarn clamping linkage 45 is fitted into the engaging hole 22f of the connecting arm portion 22e of the second yarn clamping plate 22 from below.

Therefore, the origin position of the second thread clamping plate 22 accompanying the initial setting of the thread clamping motor 36 is set to the start position 22 (S) shown in FIG. However, the start position 2 2 (S) of the second thread clamping plate 22 is the origin position when the thread clamping motor 36 is initially set, and the thread hole 22b is a position that matches the needle hole 12a of the needle plate 12. In this position, the sewing needle 11 and the thread end 7a can be inserted. Here, the link mechanism is comprised from the drive lever 38, the link board 39, the rotation lever 41, the thread clamping linkage 45, etc. FIG.

  By driving the thread clamping motor 36 by a predetermined amount, the second thread clamping plate 22 is rotated by α1 corresponding to the first angle from the starting position 22 (S) in FIG. 4 to the clamping position 22 (K) shown in FIG. Rotate around. At this time, since the first thread clamping plate 21 is at the clamping position 21 (K), the second thread clamping part 22c of the second thread clamping plate 22 moved to the clamping position 22 (K) and the clamping position 21 (K). The thread end portion 7a extending from the eye hole 11a of the sewing needle 11 is clamped by the cooperation with the first thread clamping portion 21b of the first thread clamping plate 21 in the above.

  By the further predetermined amount of driving of the yarn clamping motor 36, the second yarn clamping plate 22 becomes α2 corresponding to the second angle from the clamping position 22 (K) in FIG. 6 to the release position 22 (L) shown in FIG. Only turn clockwise. At this time, the engagement pin 27 of the second thread clamping plate 22 is engaged with the clamping arm portion 21a of the first thread clamping plate 21, and the first thread clamping plate 21 is clamped in FIG. It is rotated from the position 21 (K) to the release position 21 (L) shown in FIG.

  In this case, the distance from the rotation fulcrum of the second thread clamping plate 22 to the second thread clamping part 22c is larger than the distance from the rotation fulcrum of the first thread clamping plate 21 to the first thread clamping part 21b. In addition, since the engaging pin 27 engages with the holding arm portion 21a on the rotation fulcrum side with respect to the first yarn holding portion 21b of the first yarn holding plate 21, the first yarn holding portion of the first yarn holding plate 21 is engaged. Since 21b rotates more largely than the second thread clamping portion 22c of the second thread clamping plate 22, the thread hole 22b of the second thread clamping plate 22 has a first thread clamping portion 21b as shown in FIG. The yarn end portion 7a that has been nipped is released without being blocked by the opening.

  Incidentally, an origin detection sensor 48 (which corresponds to a first detection sensor) including a magnetic sensor (so-called proximity sensor) is provided between the detection arm portion 39a of the link plate 39 and the mounting plate 37. This origin detection sensor 48 detects the detection arm portion 39a of the link plate 39 when the second yarn clamping plate 22 is rotated to the start position 22 (S) by the driving of the yarn clamping motor 36. The level origin position detection signal is output. That is, when the origin position detection signal from the origin detection sensor 48 is at “H” level, the second thread clamping plate 22 is rotated to the start position 22 (S).

  On the other hand, a detection part 45a extended rearward from one end part of the yarn clamping linkage 45 is formed, and a release detection sensor 49 (this is a so-called proximity sensor) is formed immediately behind the detection part 45a. (Corresponding to the second detection sensor) is fixed to the frame via the mounting plate 50. The release detection sensor 49 detects the detection portion 45a when the second yarn clamping plate 22 is rotated to the release position 22 (L) by driving the yarn clamping motor 36, and detects the release position of the “H” level. Output a signal. That is, when the release position detection signal from the release detection sensor 49 is at “H” level, the second thread clamping plate 22 is rotated to the release position 22 (L).

  Next, a control system of the electronic tacking sewing machine 1 will be described. As shown in FIG. 10, the control device 55 includes a computer including an input interface 56, a CPU 57, a ROM 58, a RAM 59, an output interface 60, drive circuits 61 to 66, and the like. Connected to the input interface 66 are a first switch 18a and a second switch 18b of the foot pedal 18, an operation panel 9, an origin detection sensor 48, a release detection sensor 49, and the like.

From the output interface 60 to the sewing machine motor 67 via the drive circuit 61, to the presser motor 68 via the drive circuit 62, to the thread clamping motor 36 via the drive circuit 63, and to the thread trimming solenoid 69 via the drive circuit 64. , the X-axis drive motor 70 for moving the cloth feed mechanism via the drive circuit 65 in the lateral direction (X direction), Y-axis drive for moving the cloth feed mechanism via the drive circuit 66 in the longitudinal direction (Y direction) A drive signal is output to each of the motors 71.

  The first switch 18a is turned on when the operator depresses the foot pedal 18 to the first presser foot position, and lowers the presser foot 13 from the raised position to the lowered position (pressed position) on the upper surface of the needle plate 12. . The second switch 18b is turned on when the foot pedal 18 is depressed to the second sewing position by the operator, and sewing control is started. The ROM 58 stores sewing data for various tacking stitches, and stores in advance a control program for sewing control for forming tacking stitches to be described later.

  Next, the sewing control executed by the control device 55 will be described based on the flowchart of FIG. In the figure, symbol Si (i = 11, 12, 13...) Indicates each step. However, when the power is turned on, the thread clamping motor 36 is rotated counterclockwise by a predetermined amount in plan view by the initial setting control, and the origin position of the second thread clamping plate 22 by a locking member (not shown). That is, the start position 22 (S) is determined.

  When the work cloth W to be sewn is placed on the needle plate 12 and the foot pedal 18 is depressed to the first presser position, the presser foot 68 is driven by the presser motor 68 based on the ON signal of the first switch 18a. The work cloth W is pressed by moving to the lowered position. Next, this control is started when the foot pedal 18 is depressed to the second stage sewing position.

  This control is started. First, when the second switch 18b is ON (S11: Yes) and the thread clamping mode switch of the operation panel 9 is ON, that is, when the thread end 7a is clamped ( S12: Yes), the yarn clamping motor 36 is driven by the origin detection control, and the second yarn clamping plate 22 is rotated to the start position 22 (S) (S13). Next, when the origin position detection signal from the origin detection sensor 48 is at the “H” level (S14: Yes), the sewing machine motor 67 is driven (S15), and the sewing process for the stitches selected in advance is performed. It starts (S16).

  By the way, when the origin position detection signal from the origin detection sensor 48 is “L” level (S14: No), since the position of the second thread clamping plate 22 is abnormal, an error message is displayed on the display of the operation panel 9. Error processing such as display is executed (S27), and this control is terminated.

  Next, when the sewing process is started and the first sewing needle 11 reaches the thread clamping timing above the needle plate 12, that is, in FIG. 12, the phase angle of the main shaft is in the range of about 360 ° to 30 °. In this case (S17: Yes), by driving the thread clamping motor 36, the second thread clamping plate 22 is rotated by α1 and rotated to the clamping position 22 (K) (S18).

  At this time, when the origin position detection signal of the origin detection sensor 48 is “L” level (S19: Yes), the second thread clamping plate 22 is normally rotated to the clamping position 22 (K). When the detection signal is not at the “L” level (S19: No), it is abnormal, so that the drive of the sewing machine motor 67 is immediately stopped (S26), error processing is executed (S27), and this control is terminated.

  Next, when stitch formation of a predetermined number of stitches (for example, for 3 stitches) is completed by the sewing process (S20: Yes), it is not necessary to clamp the thread end portion 7a, and the thread clamping motor 36 is driven. Then, the second thread clamping plate 22 is further rotated by α2 and rotated to the release position 22 (L) (S21). Next, when the release position detection signal from the release detection sensor 49 is “H” level (S22: Yes), the second thread clamping plate 22 is normally rotated to the release position 22 (L). The sewing process is continued (S23).

  However, when the release position detection signal is not “H” level (S19: No), it is abnormal, so that the drive of the sewing machine motor 67 is immediately stopped (S26), error processing is executed (S27), and this control is finished. To do. When the sewing process of the tacking seam is completed (S23: Yes), the movable blade 31 is driven through the thread trimming mechanism by driving the thread trimming solenoid 69 to cut the upper thread 7 and the lower thread (S24). ). Next, the thread clamping motor 36 is driven in the reverse direction, and the second thread clamping plate 22 is rotated back to the start position 22 (S) at once (S25).

By the way, when the yarn clamping mode switch is OFF and the yarn clamping is not performed (S12: No), the yarn clamping motor 36 is driven and the second yarn clamping plate 22 passes through the clamping position 22 (K) at once. It is rotated to the release position 22 (L) (S28). Then, when the release position detection signal from the release sensor 49 is at the "H" level (S2 9: Yes), the second thread gripping plate 22 is rotated to the release position 22 (L) normally Therefore, the sewing machine motor 67 is driven (S30), the sewing process is executed (S31), the thread trimming process is executed along with the end of the sewing process (S32), and this control is finished.

  Next, the operation and effect of the electronic tacking sewing machine 1 configured as described above will be described. When the foot pedal 18 is depressed to the second sewing position, the second thread clamping plate 22 rotates to the start position 22 (S) shown in FIG. 4, so that the sewing needle 11 and the thread end 7a are accompanied with the start of sewing. Enters the needle hole 12a and the thread hole 22b. Then, the upper thread 7 is engaged with the sword tip 15d of the vertical hook 15, and the upper thread loop is expanded by the movement of the sword point 15d.

  When the first sewing needle 11 moves to the upper side of the needle plate 12 and the phase angle of the main shaft is about 360 ° to 30 °, that is, the upper thread 7 is tightened to some extent by the balance, and the length of the thread end 7a is about When the length is shortened to 2 to 3 cm, and at the time of thread clamping, the second thread clamping plate 22 is clamped by α1 corresponding to the first angle when the thread clamping motor 36 is driven by a predetermined amount. ) (See FIGS. 6 and 7), the yarn end portion 7a is securely clamped between the first clamping portion 21b of the first yarn clamping plate 21 and the second clamping portion 22c of the second yarn clamping plate 22. Then, the sewing process is continued.

  When the sewing process is continued with the yarn end portion 7a being clamped by the cooperation of the first and second yarn clamping portions 21b and 22c, the clamping position 21 by the first and second yarn clamping portions 21b and 22c. Since (K) and 22 (K) are located to the side of the position of the sewing needle 11, it is possible to reliably prevent the thread end 7a from being caught on the seam by being caught by the sword tip 15d during sewing. Can do.

  Thereafter, when the sewing process proceeds and, for example, “3 stitches” of stitches are formed, the second thread clamping plate 22 is driven by a predetermined amount by the thread clamping motor 36 by α2 corresponding to the second angle. The first thread clamping plate 21 is also rotated to the release position 21 (L) through the engagement of the engagement pin 27 simultaneously with the rotation to the release position 22 (L) (see FIGS. 8 and 9). . In this case, as described above, the thread hole 22b of the second thread clamping plate 22 is based on the fact that the rotation fulcrum of the first and second thread clamping plates 21 and 22 is shifted and the engagement position of the engagement pin 27. Is opened, the yarn end 7a can be reliably opened.

  By the way, the second thread clamping plate 22 and the thread clamping linkage 45 are provided with an upward connecting pin 46 at the tip of the thread clamping linkage 45 in the engagement hole 22f of the coupling arm portion 22e of the second thread clamping plate 22. Since it is only fitted from the lower side, that is, the connecting portion between the second thread clamping plate 22 and the thread clamping linkage 45 is configured to be disengaged, so that the thread dust adhered to the lower side of the needle plate 12 When the needle plate 12 is removed to clean the needle plate 12 and the like, the plurality of set screws fixing the needle plate 12 are removed, and the needle plate 12 is lifted upward, so that the engagement hole of the second thread clamping plate 22 is removed. The engagement of the connecting pin 46 of 22f and the thread clamping linkage 45 is easily released, and the needle plate 12 can be easily removed.

  As described above, the first thread clamping plate 21 and the second thread clamping plate 22 are arranged on the lower surface of the needle plate 12, and the first thread clamping plate 21 is pivotally attached to the first pivot pin 23 so as to be rotatable. The second thread clamping plate 22 is pivotally attached to the second pivot pin 24 so that the first and second thread clamping plates 21 and 22 are connected via the thread clamping linkage 45 by driving the thread clamping motor 36. Since the thread end 7a extending from the eye hole 11a of the sewing needle 11 is releasably clamped by turning in the same direction, the configuration of the upper thread clamping mechanism 20 can be reduced in size and simplified. Further, it is possible to reduce the size and weight of the electronic tacking sewing machine 1 and to reduce the cost.

  In addition, the rotation support point of the second thread clamping plate 22 is shifted to the back side with respect to the rotation support point of the first thread clamping plate 21, and the first thread clamping by the engagement pin 27 of the second thread clamping plate 22. Since the engagement position of the plate 21 is set between the first clamping portion 21b and the rotation fulcrum, the clamping of the yarn end portion 7a is realized, so that the upper yarn clamping mechanism 20 is further simplified and reduced in size. be able to.

  Further, since the origin position of the second thread clamping member 22 associated with the initial setting of the thread clamping motor 36 is set to the start position 22 (K), when the initial setting of the thread clamping motor 36 is executed, the second thread is held. Since the clamping member 22 rotates to the origin position which is the start position 22 (K), sewing can be started immediately at the rotation position, and the interference between the sewing needle 11 and the second thread clamping member 22 is ensured. Can be prevented.

  Further, an enlarged portion 22g is formed on the moving side of the second holding portion 22c having the yarn hole 22b of the second yarn holding plate 22 to the first yarn holding plate 21, and a part of the enlarged portion 22g is the second yarn holding plate. 22 at least at the start position 22 (K), the first yarn clamping plate 21 is superposed from the lower side. Therefore, when the second yarn clamping plate 22 rotates to the clamping position, the first yarn clamping of the enlarged portion 22g A smooth movement to the clamping position 22 (K) can be realized while maintaining a predetermined moving speed without colliding with the first thread clamping plate 21 through polymerization with the plate 21, and a clamping operation can be realized. Can be speeded up.

  Next, a modified form of the embodiment will be described.

  1) The first thread clamping plate 21 is fixed to the lower surface of the needle plate 12, and the second thread clamping plate 22 is rotated from the start position 22 (S) to the release position 22 (L) through the clamping position 22 (K). When moved, the yarn hole 22b may be released by passing through the first yarn clamping plate 21, and the yarn end portion 7a may be released.

  2] The rotation direction of the second thread clamping plate 22 and the arrangement of the first thread clamping plate 21 are opposite to those in FIG. 4, and the second thread clamping plate 22 is rotated counterclockwise in plan view. Thus, the clamping position 22 (K) and the release position 22 (L) may be realized.

  3] Instead of the thread clamping motor 36, various electric actuators such as a DC motor capable of feedback control or a linear solenoid may be used.

  4] The vertical hook 15 is not limited to a half-turn hook, and may be a full-turn hook.

  5] The shape of the thread hole is not limited to a circle, and may be various shapes such as an ellipse that is long on the left and right, a rectangle, and a polygon.

  6] The present invention is not limited to the above-described embodiments, and those skilled in the art can implement various modifications to the above embodiments without departing from the spirit of the present invention. The present invention includes such modifications.

  7) Of course, the present invention can be applied to various sewing machines having various upper thread clamping mechanisms having first and second thread clamping members attached to the lower side of the needle plate.

It is a side view of the electronic tacking sewing machine concerning the example of the present invention. It is a perspective view of an upper thread clamping mechanism. It is a front view of a bed part. It is a fragmentary top view of the cylinder bed part explaining a starting position. It is the EE line vertical front view of FIG. It is a fragmentary top view of the cylinder bed part explaining a clamping position. It is the GG line vertical front view of FIG. It is a partial top view of a cylinder bed part explaining a release position. It is the II sectional view front view of the II line | wire of FIG. It is a block diagram of the control system of an electronic tacking sewing machine. It is a flowchart of sewing control. It is a figure which shows the movement locus | trajectory of a balance and a needle bar with respect to the phase angle of a main axis | shaft.

DESCRIPTION OF SYMBOLS 1 Electronic bar clamp sewing machine 2 Bed part 7a Thread end part 12 Needle plate 12a Needle hole 20 Upper thread clamping mechanism 21 First thread clamping board 21b First clamping part 21d Stopper part 22 Second thread clamping board 22b Yarn hole 22c Second clamping Part 22f Engagement hole 22g Enlarged part 23 First pivot pin 24 Second pivot pin 26 Pull coil spring 35 Rotation drive mechanism 36 Thread clamping motor 45 Thread clamping linkage 46 Connection pin 48 Origin detection sensor 49 Release detection sensor

Claims (10)

In the upper thread clamping mechanism of the sewing machine that releasably clamps the thread end of the upper thread extending from the stitch hole of the sewing needle under the needle plate of the bed part,
A first thread clamping member pivotally attached to a lower surface of the needle plate by a vertical pin member ;
A second thread pinching member that has a thread hole that allows a needle to pass through the needle hole of the needle plate and that clamps the thread end in cooperation with the first thread clamping member; A second thread clamping member pivotally attached by a vertical pin member;
The second thread clamping member includes a starting position where the thread hole matches the needle hole of the needle plate, a clamping position for clamping the thread end part in cooperation with the first thread clamping member, and the thread end part. and a rotation driving means for driving rotation over a release position for releasing the clamping,
When the second thread clamping member rotates from the clamping position to the release position, the first thread clamping member cooperates with the second thread clamping member to clamp the thread end, and the thread An upper thread clamping mechanism of a sewing machine configured to be rotatable over a release position for releasing clamping of an end portion . The clamping position is at a position where the second thread clamping member is rotated by a first angle with respect to the start position, and the release position is in the same direction as the first angle with respect to the clamping position. The upper thread holding mechanism of the sewing machine according to claim 1, wherein the upper thread holding mechanism is at a position rotated by a second angle . An elastic member that urges the first thread clamping member toward the clamping position and a locking member that locks the first thread clamping member at the clamping position against the urging force of the elastic member are provided. The upper thread clamping mechanism of the sewing machine according to claim 2 . The rotation support point of the first thread clamping member is provided on the base side in the length direction of the bed from the needle hole, and the rotation support point of the second thread clamping member is further than the rotation support point of the first thread clamping member. The upper thread clamping mechanism of the sewing machine according to any one of claims 1 to 3, wherein the upper thread clamping mechanism is provided on a root side . The rotation driving means includes an electric actuator and a link mechanism that connects the electric actuator to the second thread holding member, and the connection between the second thread holding member and the connecting member included in the link mechanism is performed as described above. The upper thread clamping mechanism of the sewing machine according to any one of claims 1 to 4, wherein the needle thread clamping mechanism and the second thread clamping member are released as they are removed from the bed portion . The connecting portion of the second thread clamping member is disposed on the upper side of the connecting portion of the connecting member, the connecting portion of the connecting member positioned on the lower side is provided with an upward connecting pin, and the second thread clamping member positioned on the upper side 6. The upper thread clamping mechanism of the sewing machine according to claim 5 , wherein an engagement hole that can be engaged with the connection pin is formed in the connection portion . The upper thread pinching mechanism of the sewing machine according to claim 5 , wherein an origin position of the second thread clamping member according to an initial setting of the electric actuator is set to the start position . An enlarged portion is formed on the moving side to the first yarn clamping member at the tip end portion having the yarn hole of the second yarn clamping member, and a part of the enlarged portion is at least at the start position of the second yarn clamping member. The upper thread clamping mechanism according to any one of claims 1 to 7, wherein the upper thread clamping mechanism is superposed on a single thread clamping member. The upper thread clamping mechanism according to any one of claims 1 to 8, further comprising a first detection sensor that detects that the second thread clamping member is at a start position . The upper thread clamping mechanism of the sewing machine according to claim 9 , further comprising a second detection sensor that detects that the second thread clamping member is in a release position .