JPS5934387B2 - buttonhole sewing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a buttonhole sewing machine, and particularly to a buttonhole sewing machine, in which a core string is sewn into a buttonhole stitch, and after the stitch is formed, an upper thread connected between a fabric stitch and a needle is formed. This invention relates to a buttonhole sewing machine that is equipped with a cutting mechanism that cuts a core string that is continuous between a seam and the tip of a core string guide by moving across the stitch.

In this type of sewing machine, the upper thread T is used to ensure the formation of the next seam and to properly sew the core cord into the seam.
As shown in FIG. 7A, the core string S must be cut at a position away from the final needle drop point in the direction of stitch formation, and the cut pieces must be clamped.

However, during the formation of the next stitch, the movable blade must be moved back in preparation for the next thread cut, and as a result, the cut ends of the needle thread and core string, which had been clamped, are released and free. It becomes a state.

In this case, if the cut ends are long, they will move over the seam formed by the vibration of the sewing machine and be sewn into the seam, and their tips will protrude to the side or above the seam, causing the seam to break. This has the disadvantage of spoiling the aesthetic appearance, so the cut end must be kept as short as possible.

In order to shorten the cut end, it is necessary to bring the final needle drop as close as possible to the cutting position by the movable blade and the fixed blade.

However, in order to bring the needle drop closer to the cutting position, as shown in Figure 8, if the final needle drop is performed near the edge of the needle through hole of the presser foot, the first needle drop for the next stitch formation will be Since this is done near the final needle entry point, the core string, one end of which is clamped by the clamp plate, is placed at a nearly right angle downward from above the inner peripheral edge of the presser foot that forms the needle through hole. Since the seam is sewn in a bent state, a strong resistance force is applied to the seam, which makes the thread tightness of the seam worse, making it easier for the seam to come undone, which reduces the quality of the product. be.

Also, when forming stitches on fabric with steps, the fabric presser foot must be tilted to press the fabric, and for this reason, the needle drop position should be near the edge of the needle through hole. However, there are cases where the needle collides with the side surface of the needle through hole and is damaged, so there is a limit to how close the needle drop point can be to the cutting point.

In this invention, the cut ends of the needle thread and core string that remain for a long time from the needle and core string guide due to the thread trimming performed at the end of the previous stitch formation are removed from the seam of the fabric by the next stitch formation. The part protruding from the tip is cut short by the return movement of the movable blade after the start of stitch formation between the movable blade and the blade of another fixed blade located close to the needle drop point. By configuring the needle to be configured as shown in FIG. To provide a buttonhole sewing machine capable of shortening the cut end of an upper thread.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.The needle bar 2 is driven via a start/stop mechanism (not shown) when the sewing machine is started, and the needle bar 2 supporting the needle 1 at its lower end is driven by the start/stop mechanism (not shown).
moves up and down at a certain position, and its horizontal amplitude and base line change, and a cloth feeding mechanism (described later) reciprocates the cloth in a direction perpendicular to the direction of needle vibration to form a buttonhole stitch. Then, on the upper surface of the bed 3 of the cycle sewing machine that stops after the formation, the base of the feed arm 5 whose tip is bent along the lower surface of the arm 4 is moved to the first position in conjunction with the drive of the sewing machine.
, 2 is rotatably connected to a feed mechanism (not shown) that reciprocates left and right as shown in FIG. A cloth presser foot 7 having a long needle through hole 6 formed in parallel to the moving direction of the feed arm 5 is supported.

This cloth presser foot 7 is a cloth support provided on the bed 3 (not shown).
The cloth is sandwiched between the sewing machine and the sewing machine, and the cloth is reciprocated from side to side in conjunction with the cycle operation of the sewing machine.

A guide 7 frame 8 is provided at the tip of the feed arm 5 so as to form a guide hole parallel to the moving direction of the feed arm 5 between the tip and the upper end surface of the feed arm 5, and the lower end is connected to the bottom surface of the jaw of the sewing machine. It supports the lifting rod 9 projecting downward from the top so that it can move up and down,
A support piece 11 is fixed to one side of the lower end of the lifting rod 9, and rotatably supports a roller 10 that fits into a guide hole at the tip of the feed arm 5.

This lifting rod 9 is moved up and down via a lifting mechanism (not shown) in the sewing machine arm in conjunction with the operation of a foot pedal (not shown) appropriately placed below the sewing machine table (not shown). As it descends, the tip of the feed arm 5 is pressed downward via the rollers 10 and the cloth support 7 is pressed against the fabric support, and as it rises, the tip of the feed arm 5 is pushed downward via the rollers 10 and the guide frame 8. The tip portion is lifted up and the presser foot 7 is raised from the cloth support.

As shown in FIG. 2, on one side of the feed arm 5, the tip of a support plate 12 is placed in relation to a horizontal axis (not shown) placed on the lower surface of the arm of the sewing machine parallel to the direction of movement of the feed arm 5. A bent support rod 13 is fixed so that its lower end extends below the chin, and a tubular core string guide 14 is provided at the lower end of this support rod 13 to guide a core string and whose tip protrudes close to the needle.
will be established.

This support plate 12 is configured so that its position is changed when the base line of the amplitude of the needle 1 is changed and when the direction of stitch movement is reversed so that the core string guide 14 always precedes the needle 1 in the direction of movement of stitch formation. The converting mechanism is as described in the specification of Japanese Patent Application No. 1972-1972 filed by this applicant, and its explanation will be omitted here.

As shown in FIGS. 4 and 5, the presser foot 7 is provided with a cutting mechanism for cutting the upper thread and core string of the buttonhole seam.

Therefore, to explain this cutting mechanism, the blade part 1 is formed in an L shape so as to surround the two sides of the left end of the rectangular needle through hole 6 of the presser foot 7, and is perpendicular to the moving direction of the feed arm 5.
5a and a fixed blade 1 provided with a blade portion 15b along the direction of movement thereof
5 is fixed so that its blade part 15a is located at a certain distance in the direction of stitch progression from the final needle drop point, and the blade part 15b is closer to the needle drop point than the blade part 15a, and the bent part The center part of the movable blade 16 formed in an L-shape on the upper surface is rotatably supported by a stepped screw 17, and one side edge of one end of the movable blade 16 is provided with a clockwise rotation of the movable blade 16. A blade that traverses the path of the needle thread that connects the stitches formed in the cloth and the needle 1, that is, the path of the needle 1, captures the needle thread, and cuts it in cooperation with one blade portion 15a of the fixed blade. A blade part 19 is formed to cross the path of the core string that connects the part 18, the seam, and the core string guide 14, capture the core string, and cut it in cooperation with the blade part 15a. By rotating the movable blade 16 in the counterclockwise direction, the needle thread and the cut ends of the core cord protruding from the seam ends formed in the cloth are captured and cut into the other fixed blade part 15b.
A blade portion 20 for cutting the cut end short is formed by cooperation with the movable blade 16, and a pin 21 is implanted on the upper surface of the other end of the movable blade 16.

A movable blade 16 and a fixed blade 15 each extend above one blade part 15a of the fixed blade 15 at the front and rear ends of the left end of the presser foot 7.
Before the upper thread is cut between the movable blade 16 and the blade part 15a of
Clamp plate 2 for clamping it between the top surface of
2 and a clamp plate 23 for clamping the core cord between the upper surface of the movable blade 16 and the upper surface of the movable blade 16 before the core cord is cut.

Next, the operating mechanism of the uncut mechanism will be explained.

As shown in FIGS. 1 and 3, on the other side of the tip of the feed arm 5, a locking pin 24 is provided on the upper end surface of the tip and projects laterally, and the pin 21 of the movable blade 16 is loosely fitted on the lower edge. A movable plate 26 provided with forked portions 25 is supported so as to be horizontally movable from side to side, and a spring hook provided near the rear end is connected to a pin 27.
A coil spring 29 is passed between the spring hook provided at the extended end of the guide frame 8 and the piece 28, so that an elastic acting force is always applied to the movable plate 26 to the right in FIG.

Above the movable plate 26, a locking piece 30 for locking the locking pin 24 is formed on the lower edge of the distal end with its right edge side inclined, and a cam portion 31 is formed on the lower edge of the intermediate portion. The rear end of the locking plate 32 is supported by a step screw 33 so as to be rotatable around a horizontal axis perpendicular to the moving direction of the feed arm 5, and a spring 34 wound around the step screw 33 always rotates the locking plate 32 clockwise. A locking pin 35 that can be locked to the cam portion 31 is installed on the side surface of the lower end of the branch 11 of the lifting rod 9 by applying a rotational force.

A connecting shaft 38 is provided with a guide pin 37 that projects laterally at a slightly lower portion than the upper end of the transmission link 36 on the intermediate side surface of the feed arm 5.
The feed arm 5 is rotatably supported around a horizontal axis perpendicular to the moving direction thereof, and its lower end and the rear end of the moving plate 26 are rotatably connected by an intermediate link 39.

One end of a connecting link 40 is rotatably connected to the intermediate portion of the transmission link 36, and the other end of the connecting ring 40 has an L-shape with the intermediate portion rotatably supported on the side surface of the rear end of the sending arm 5. It is rotatably connected to one end of the operating link 41 extending upwardly.

Although the other end of this operating link 41 is not shown,
The lifting lever 9 is moved by the lifting mechanism, and before the lifting lever 9 is raised by lifting the lifting lever 9 using the foot pedal, the operation link 41 is rotated counterclockwise, and the lifting lever 9 is rotated counterclockwise. Rod 9
The rotation is released by the lowering operation.

A guide pin 37 of the connecting shaft 38 is provided on the side of the jaw of the sewing machine.
A cam plate 44 formed with a cam groove 42 into which the
Rotatably supports one end of.

The present invention has the above configuration, and its operation will be explained next.

The state shown in FIG. 1 shows the state in which the seam formation has been completed, and at this time, the movable plate 26 is positioned to the right by the action of the coil spring 29, and the locking pin 24 is the locking piece of the locking plate 32. 3
The engagement pin 35 of the branch 11 of the lifting rod 9 is located on the right side of 0.
is located away from the cam portion 31 of the locking plate 32 to the right, and the guide pin 37 of the connecting shaft 38 is located in the cam groove 42 of the cam plate 44.
It is located near the left edge of.

In this state, if the lifting rod 9 is raised using the foot pedal, the operating link 41 is rotated counterclockwise at the initial stage of the operation, and the transmission link 36 is thereby connected to the connecting shaft 38 via the connecting link 40. The moving plate 26 is rotated clockwise around the intermediate link 39 to move the moving plate 26 to the left against the action of the coil spring 29.

As the moving plate 26 moves, the locking pin 24 engages with the right edge of the locking piece 30 of the locking plate 32, and the locking plate 32 is pushed out counterclockwise against the action of the spring 34 and engaged. After the stop piece 30 moves to the left, the stop plate 32 rotates back clockwise due to the action of the spring 34, and at the same time, the rotation of the operating link 41 is stopped.

This movement of the movable plate 26 causes the two-pronged portion 25 and the pin 2 to
1, the movable blade 16 is rotated clockwise in FIG.
One blade part 18 on one side edge captures the upper thread T that is connected to the needle from the final needle drop point of the stitch formed on the cloth, and the other needle part 1
9 captures the core string S connected to the core string guide 14 from the seam, and then clamps the needle thread T and the core string S between the lower surfaces of the clamp plates 22 and 23 and the upper surface of the movable blade 16, respectively, and The needle thread T and the core string S are cut between the sections 18 and 19 and one blade section 15a of the fixed blade 15 (see A in FIG. 7).

Therefore, when a new cloth is inserted into the lower surface of the presser foot 7 and the lifting rod 9 is lowered to form the next stitch, the rotation of the operating link 41 is released, but the movable plate 26 Since the locking pin 24 is locked by the left edge of the locking piece 30 of the locking plate 32, it does not return to the right, and the movable blade 16 is maintained in the state shown in FIG. 7A.

When the sewing machine is driven, the feed arm 5 moves to the right in Figs. 1 and 6 (left in Fig. 2.5.7), and moves the core string from near the final needle drop point to the right. Stitch formation progresses as S is sewn in.

When the needle drop point reaches outside the rotation area of the movable blade 16 as the stitch formation progresses, as shown in Fig. B of Fig. 7, the locking plate 32 is moved as shown in Fig. B of Fig. 6. The cam part 31 is the branch 1
The locking plate 32 is engaged with the first locking pin 35 and the locking plate 32 is engaged with the spring 34 again.
As a result, the lock pin 24 of the moving plate 26 is unlocked by the locking piece 30, and the moving plate 26 returns to the right by the action of the coil spring 29. The movable blade 1
6 is moved back in the counterclockwise direction, and this back movement causes B in FIG.
As shown in the figure, the cut end of the clamped needle thread T and the cut end of the core string S are connected between the blade part 20 on the other side edge of the movable blade 16 and the other blade part 15b of the fixed blade 15. cut short.

Note that when the locking pin 24 is released by the locking piece 30, the blade portions 15a of the movable blade 16 and the fixed blade 15 and the clamp plate 222
Due to the abrasion resistance between coil spring 2 and 3, the moving plate 26
If it does not return due to the action force of 9, the upper front end surface of the transmission link 36 will come to engage with the pressing pin 43° of the cam plate 44 due to further movement of the feed arm 5 after the above-mentioned release, and as a result, the pressing pin 43 will cause the upper end front end surface of the transmission link 36 to engage with the pressing pin 43° The transmission link 36 is forcibly rotated counterclockwise, and the movable blade 16 is reliably moved back by this rotational force and the acting force of the coil spring 29.

Then, as shown in Fig. 0 of Fig. 6, the subsequent feeding arm 5
As a result of this movement, the cam plate 44 is rotated clockwise while being guided by the guide pin 37 of the connecting shaft 38, and the pressing pin 43 is moved to a position out of engagement with the upper end of the transmission link 36.

In this case, when the thickness of the cloth to be sewn changes, the position of the tip of the feed arm 5 changes in the vertical direction via the cloth presser foot 7, but the cam plate 44 also changes via the guide pin 37 of the connecting shaft 38. The suppression pin 43 is rotated following the change, and the feed arm 5
It changes vertically in response to the vertical change of the transmission link 36 due to the vertical change of The forced return timing of the blade 16 can always be kept constant.

Therefore, when the feed arm 5 reaches the rightmost position and the sewing on one side of the buttonhole stitch is completed, one side of the bar tacking is performed, and then the base line of the needle bar 2 is changed and at the same time The moving direction of the feed arm 5 is reversed and moved to the left in Figs. 1 and 6 (to the right in Fig. 2 and 5.7), and the other side sewing is performed, and the feed arm 5 moves to the original When it has almost returned to its position, the other bar tacking is performed, the buttonhole stitch is completed, and the sewing machine stops.

After this stop, the lifting lever 9 is raised, and as described above, the upper thread T is connected to the final needle drop point of the stitch and the needle 1, and the core is connected to the end of the stitch and the core string guide 14. String S is movable blade 1
It is cut by the forward movement of 6.

As described above, this invention utilizes the reciprocating movement of the movable blade disposed on the presser foot after forming the buttonhole stitch to connect the needle thread to the stitch of the fabric and the needle, and the core to connect the stitch to the core string guide. In a buttonhole sewing machine in which the string is cut and clamped at a distance in the direction of stitch progress, the needle thread and core string remaining at the tip of the new stitch are cut after the start of the next stitch formation. Since the end is cut short by the back movement of the movable blade, it is possible to maintain a sufficient distance between the final needle drop point of the stitch and the edge of the needle through hole in the presser foot. Since there is no need to sew with the core cord bent at an extreme angle at the beginning of seam formation, it is possible to form seams with good thread alignment, and also to create seams with uneven fabrics. When forming a seam, even when pressing the fabric with the presser foot tilted, the needle collides with the end surface of the needle through hole of the presser foot, resulting in damage to the needle or presser foot. Because there is nothing,
It has excellent safety, and in addition, the cut ends of the needle thread and core string that remain at the tip of the seam can be shortened when the next seam is formed, so that the needle thread and core string can be fixed in the direction of stitch progression due to their rigidity. This prevents the cut ends from being sewn in by the final bar tack of the seam, and even if they are sewn in by the bar tack, they will not be sewn into the seam. Since the cut end is completely sewn into the seam, the tip of the cut end does not protrude to the side of the seam, and it is possible to create a beautiful buttonhole seam in terms of appearance.

[Brief explanation of drawings]

Figure 1 is a left side view of the sewing machine, Figure 2 is a right side view of the sewing machine, Figure 3 is a perspective view showing the operating mechanism of the thread cutting mechanism, and Figure 4 is the presser foot mechanism and the thread cutting mechanism arranged therein. FIG. 5 is a top view of the presser mechanism, FIG. 6 is an explanatory diagram showing the operating order of the thread cutting mechanism, and FIG. 7 corresponds to FIG. 5, and the operating order of the thread cutting mechanism. FIG. 8 is an enlarged sectional view taken along line A--W in FIG. 7.

Claims (1)

[Claims] 1. A start/stop mechanism that operates to drive the sewing machine by the start operation and stop after forming a certain number of stitches, a feed arm that reciprocates on the bed surface in conjunction with the drive of the sewing machine, and a support at the tip of the feed arm. The presser foot has a long needle through hole formed in the center in parallel to the direction of movement of the feed arm and moves the fabric as the feed arm moves, and a presser foot that moves up and down in conjunction with the drive of the sewing machine and moves in the direction of movement of the fabric. The needle swings in the direction perpendicular to the needle and forms a buttonhole stitch on the fabric in the needle through hole of the presser foot in cooperation with the thread catcher located below the bed surface, and the needle is always positioned in the direction of stitch progress. The core string guide mechanism has a core string guide that guides the core string so as to be sewn into the seam, and a core string guide mechanism that is fixed to the fabric presser foot and moves the stitch from the final needle at two positions across the path of the final needle of the seam. A fixed blade that has a first blade part that is separated in the direction of the needle and a second blade part that is closer to the final needle and runs along the stitch progressing direction, and a presser foot that can reciprocate to cross the path of the final needle. a movable blade that is supported by the movable blade and that cooperates with the first blade part of the fixed blade in its forward movement and cooperates with the second blade part in its backward movement to cut the needle thread and the core string, respectively;
The presser foot is clamped between the movable blade and the cut end of the needle thread on the needle side and the cut end of the core string on the core string guide side, which are cut between the first blade part of the fixed blade and the movable blade. A clamp plate placed on the sewing machine and a movable blade are arranged in relation to the sewing machine so as to reciprocate, and when the sewing machine is stopped, the needle thread is connected to the stitches of the completed cloth and the needle, and the core string is connected to the stitches and the core string guide. A button having an operating mechanism that moves a movable blade forward to cut the needle thread and then moves the movable blade back to cut the cut end of the core string and the needle thread that protrudes from a new seam end after the start of seam formation. Hole sewing machine.