JP3542162B2 - Overlock sewing machine - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to an overlock sewing machine capable of performing not only overlock sewing but also sewing forms such as double chain stitching and flat stitching.
[0002]
[Prior art]
In overlock sewing machines, in addition to the overlock sewing, there is a type in which double chain stitching or flat sewing can be appropriately switched and executed. One of means for realizing this is a lower overlock sewing machine. It has been considered to add a lower looper for double chain stitching or flat sewing in addition to the looper and the upper looper. However, in this case, there is a problem that the looper driving mechanism is complicated, and there are many difficulties in performing the looper driving mechanism. Therefore, at present, the lower looper for overcast sewing is also used for double ring sewing and flat sewing. Has been proposed and implemented.
[0003]
In this overlock sewing machine, the lower looper swings left and right in the overcast sewing. However, when performing double chain stitching or flat sewing as shown in FIG. It is designed to rock. The illustrated seam is a double loop seam of two needles and three threads constituted by two needle threads and one looper thread. In this seam, two needle threads T1 and T2 are parallel. And a looper thread TL is used for cross stitching between these two needle threads.
[0004]
In order to form such a stitch, it is necessary to keep the needle thread in an appropriate positional relationship with the sewing needle during the stitch forming operation. That is, when performing double chain stitching or flat stitching, as shown in FIG. 11A, the needle threads T1 and T2 captured by the lower looper L return the lower looper L to the returning operation (leftward in the figure). ), The sewing needles N1 and N2 fall to the left side of the needle thread TL and move in the above-described triangle. In some cases, the sewing needles N1 and N2 did not fall, and an appropriate stitch was not formed.
[0005]
In view of this, the present applicant has previously proposed in Japanese Patent Application No. 5-157687 a device capable of reliably performing double chain stitching and flat stitching using a lower looper for overcast stitching.
In the above prior art, a lower looper shaft that swings left and right and back and forth in conjunction with a main shaft of a sewing machine, a thread handling hook that can swing back and forth, and left and right, and a forward and backward swinging motion of a lower looper shaft is used for the thread handling. A front-rear movement transmitting means for transmitting to the hook, and a left-right movement transmitting means for transmitting the left-right swinging movement of the lower looper shaft to the thread handling hook, wherein a claw provided on the thread handling hook is used for other than overlock sewing. An overlock sewing machine is described which holds a sewing needle so as to fall into a triangle formed by a looper thread, a lower looper and a needle thread when the needle falls when sewing.
[0006]
[Problems to be solved by the invention]
However, in the above-described prior art, the thread separating member always swings in the left-right direction during the sewing operation, regardless of whether the sewing is the overcasting or the other sewing. For this reason, in the overlock stitching that does not require the operation of the thread separating member, the thread separating member performs unnecessary movement, and this causes the thread separating member and the right and left oscillating motion transmission mechanism to friction and deteriorate more than necessary. Was causing it.
[0007]
In addition, since the thread separating member swings right and left, there is a risk that the thread separating member may get caught in the empty ring formed at the time of the overlock sewing. However, since the thread separating member is configured to be located behind the empty ring forming hole in the overcast sewing, the possibility that the entanglement between the empty ring and the yarn separating member occurs is considerably low, but It is impossible to completely limit the possibility, and even if the empty ring touches even a small part of the thread separating member, the swinging movement of the member forcibly winds the empty ring, damaging the sewing product or operating the sewing machine. There was a danger of falling into an impossible state.
[0008]
SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide an overlock sewing machine capable of reducing abrasion and deterioration of a thread handling member and the like and preventing occurrence of an accident in which an empty ring is entrained by the thread handling member. And
[0009]
[Means for Solving the Problems]
According to the present invention, there is provided a selecting means for selecting either one of the overlock stitching and the double chain stitch or the flat stitch, which is a sewing mode other than the overlock stitching, and selecting a sewing mode other than the overcast stitching. When the overlock sewing is selected, the lower looper performs the right and left swinging motions simultaneously when the front and rear swinging motions and the left and right swinging motions are selected. A thread separating member held so as to be able to swing, a longitudinal movement transmitting means for transmitting the swinging movement of the lower looper in the front-rear direction to the yarn separating member, and a yarn swinging movement of the lower looper in the left-right direction. A left and right motion transmitting means for transmitting to the discriminating member, and when a sewing mode other than the overcast stitching is selected, the thread discarding member performs a front, rear, left and right combined motion in synchronism with the combined front and rear and left and right motion of the lower looper. Captured by the looper The needle thread is kept in a predetermined positional relationship with respect to the sewing needle, and at the time when the overlock stitching is selected by the sewing form selecting means, the thread separating from the lower looper performed by the left and right motion transmitting means. A blocking means for blocking transmission of the swinging motion to the member is provided.
[0010]
[Action]
In the present invention, when double chain stitching or flat stitching, which is sewing other than the overlock stitching, is selected by the selection means, the lower looper moves in the front-rear direction and the left-right direction. The motion is transmitted to the yarn separating member via the motion transmitting means, and the yarn separating member swings back and forth and right and left. Thus, the needle thread captured by the lower looper is maintained in an appropriate positional relationship with respect to the sewing needle, and the double chain stitch or the flat stitch is reliably performed. Further, when the overlock stitching is selected by the selecting means, the lower looper performs only the left-right movement, so that the thread separating member does not swing in the front-rear direction, and furthermore, the selection is interrupted. Since the means is actuated and the transmission of the movement in the left and right direction from the lower looper to the thread separating member is interrupted, the thread separating member does not swing in the left and right direction and is completely stopped. Therefore, it is possible to minimize wear and deterioration of the yarn separating member, the left and right motion transmitting means, and the like, and it is also possible to prevent the occurrence of an accident involving the ring breaking by the yarn separating member.
[0011]
【Example】
An embodiment of the present invention will be described below with reference to FIGS.
FIG. 1 is a perspective view illustrating the appearance of the overlock sewing machine according to the present embodiment.
In the figure, this overlock sewing machine includes an arm 1 and a bed 2, and two sewing needles N 1 and N 2 are provided on the arm 1 so as to be able to move up and down, and a needle plate 3 is provided on the bed. I have. Reference numeral 4 denotes a lower looper provided below the needle plate, and is provided so as to be able to swing back and forth and right and left by a mechanism described later. Although not particularly shown here, the overlock sewing machine is provided with a well-known upper looper that can operate in synchronization with the lower looper, and a well-known overcast stitch is formed by cooperation of the two loopers. It has become so.
[0012]
FIG. 2 is an enlarged perspective view of the components of the embodiment, and FIG. 3 is an exploded perspective view of what is shown in FIG. In each of the drawings, reference numeral 6 denotes a hook rotation shaft fixed to a sewing machine frame (not shown), and extends in the front-rear direction (the direction indicated by an arrow AB). Reference numeral 7 denotes a support member having one end rotatably attached to the hook rotation shaft 6. This support member is bent in an L-shape, and the lower end of the hook swing arm 9 is rotatable by an auxiliary swing pin extending in the left and right direction (the direction indicated by the arrow CD) at the other end. It is connected to. Reference numeral 10 denotes a thread handling hook (thread handling member) fixed to the upper end of the hook swing arm 9, and a pair of thread handling claws 10a and 10b projecting forward are formed at the upper end thereof. Have been. Reference numeral 11 denotes a left-right swing transmission pin projecting from the hook swing arm 9, and reference numeral 12 denotes a front-rear swing transmission pin similarly projecting from the hook swing arm 9.
[0013]
On the other hand, reference numeral 13 denotes a lower looper drive shaft supported by the sewing machine frame, which can swing in the axial direction (front-rear direction) and the rotation direction. To the lower looper drive shaft 13, the lower looper support arm 5 for supporting the lower looper 4 is fixed, and the hook swing cam 14 and the swing transmission arm 15 are fixed. The hook swing cam 14 is provided such that the peripheral surface thereof can face one end of the left and right swing transmission pin 11. A large diameter portion 14a and a small diameter portion 14b are formed on the peripheral surface of the hook swing cam 14. The swing transmission arm 15 is formed with a forked portion 15a at an upper portion thereof, and the fore-and-aft swing transmission pin 12 is fitted into the forked portion 15a.
Reference numeral 16 denotes a winding spring inserted through the hook rotating shaft. One end of the winding spring is engaged with a sewing machine frame (not shown), and the other end of the winding spring is engaged with the hook swing arm 9. The arm 9 is constantly biased rightward, and the biasing force causes the left-right swing transmission pin 11 to always contact the peripheral surface of the hook swing cam 14.
[0014]
In the above-described configuration, when the lower looper shaft 13 is rotated by a well-known rotation drive mechanism and the lower looper 4 rotates left and right, the hook swing cam 14 fixed to the lower looper shaft 13 swings. The hook swing cam 14 rotates and the right and left swing transmission pins 11 alternately contact the large-diameter portion 14a and the small-diameter portion 14b of the hook swing cam 14. As a result, the thread handling hook 10 fixed to the hook swing arm 9 swings right and left about the hook rotation shaft 6 together with the support member 7. That is, a left-right motion transmitting unit that transmits the left-right swing rotation of the lower looper 4 to the hook swing arm is configured.
[0015]
When the lower looper 4 swings in the front-rear direction (axial direction) together with the lower looper shaft 13 by a well-known front-rear drive mechanism, the swing transmission arm 15 fixed to the lower looper shaft 13 swings in the same direction. Then, the forward / backward swing transmission pin 12 is pressed in the forward / backward direction, and the hook swinging arm 9 rotates and swings around the auxiliary swinging pin 8 in the forward / backward direction. Accordingly, a left / right motion transmitting means for transmitting the forward / backward swinging motion of the lower looper 4 to the thread separating hook 10 by the thread separating hook 10 and the like by the lower looper shaft 13, the swing transmitting arm 15, and the front and rear swing transmitting pin is configured. Have been.
[0016]
Further, the overlock sewing machine in the present embodiment is provided with a blocking means capable of blocking the motion transmitting operation by the left / right motion transmitting means 2.
4 and 5 are views showing the dust blocking means. FIG. 4 is a side view, and FIG. 5 is a bottom view. In the figure, reference numeral 20 denotes a mounting plate fixed to a sewing machine frame 2a in the sewing machine bed 2, and two guide pins 21 are projected from an upper surface portion 20a thereof. Reference numeral 22 denotes a moving member that is placed on the upper surface portion 20a of the mounting plate 20, and elongated holes 22a, 22a through which the guide pins 21, 21 can be movably inserted are formed in an intermediate portion thereof. A contact member fixed to the upper surface of the support member within the range of the elongated hole, and an inclined surface 23aga is formed on the upper surface. The inclined surface 23a is inclined upward from the front end to the rear end, and enters between the lower surface of the support member and the sewing machine frame 2a when the moving member advances, and comes into contact with the lower surface of the support member. ing.
[0017]
Reference numeral 24 denotes a switching lever (selection means) for selecting one of the overcast stitching and the other stitching modes, ie, double chain stitching or flat stitching, as a stitching mode to be executed. One end of the switching lever 24 is fixed to a rotating shaft 25 rotatably supported by the sewing machine frame 2a. By rotating the switching lever 24 to S1, the switching lever 24 is interlocked with the selection means and the like. A well-known interlocking mechanism enables the lower looper shaft 13 to swing in the front-rear and left-right directions, and stops the movement of the upper looper 4 in the left-right direction. Further, when the switching lever 25 is switched to S2, a well-known interlocking mechanism interlocking with the selecting means causes the lower looper shaft 13 to rotate and swing, and enables the driving of the upper looper. .
Reference numeral 26 denotes a tension spring stretched between the mounting plate 20 and the moving member 22, which urges the moving member 22 in the advance direction (the direction of the arrow E) and bends at one end of the moving member 22. The formed locking portion 22b is always brought into contact with one end of the switching lever.
[0018]
In this embodiment having the blocking means configured as described above, when the switching lever 24 is set to the position S1 and double chain stitching is selected, the lower looper shaft 13 is linearly moved forward and backward as described above. The lower looper 4 performs a combined front-rear, left-right movement in order to perform a rotational swing movement while performing a simple swing movement. At this time, since the moving member 22 in the blocking means is held at the retracted position by the switching lever 24, the contact member 23 does not act on the supporting member 7 at all, and the hook swing cam 14 and the left and right swing transmission are performed. The pin 11 is kept in a contact state.
[0019]
For this reason, the yarn separating member 10 performs the rotational swinging movement in the front-rear direction around the auxiliary swinging pin 8 by the rotational swinging movement and the back-and-forth movement of the lower looper shaft 13, and the yarn swinging member 10 Rocking motion in the left and right directions. As a result, the yarn handling hook 10 moves along a substantially D-shaped trajectory as shown in the plan view of FIG. When the lower looper 4 that has captured the needle thread inserted through the sewing needles N1 and N2 reaches the rightmost position, the sewing needles N1 and N2 reach near the top dead center, and the thread handling hook 10 is moved to the position shown in FIG. As shown in (a) and (b), it is located at P1 in the forefront position.
[0020]
Thereafter, when the lower looper 4 moves in the backward direction (leftward in the figure), the needle threads T1 and T2 captured by the lower looper 4 move in the opposite direction (rightward in the figure) along the lower looper 4. At this time, since the claw portions 10a and 10b of the thread handling hook are moving to the left as shown in FIGS. 7C and 7D, the claw portions 10a and 10b The needle thread is held and the leftward movement of both needle threads is prevented. Therefore, the triangle formed by the needle threads T1, T2, the lower looper 4, and the looper thread TL is formed so as to surround the ascending / descending path of the sewing needle, and both the sewing needles N1, N2 surely fall within the triangle. Descend.
[0021]
On the other hand, when the switching lever 24 is set to S2, the lower looper shaft 13 performs only the rotational rocking motion and stops the rocking in the front-rear direction, so that the lower looper 13 performs only the rocking motion to the left and right. The stitch forming operation is performed. At this time, since the hook swing cam 14 constituting the left and right movement transmitting means performs a rotational swing movement together with the lower looper shaft 13, when the hook swing cam 14 is connected to the left and right swing transmission pin 11, As in the case of the above-mentioned double chain stitching, the thread separating hook 10 swings in the left-right direction. In the present embodiment, the left-right swing transmission pin 11 and the hook swing cam 14 are separated by the blocking means. Because of the separation, the yarn separating hook 10 also stops rotating and swinging to the left and right, and is completely stopped.
[0022]
That is, when the switching lever 24 is moved to S2, the moving member 22a is moved in the direction of the arrow E by the urging force of the tension spring 26, and the contact member 23 is moved as shown by the one-dot chain line in FIG. It penetrates between 2a and the lower surface of the support member 7, and the slope 23a presses the lower surface of the support member 7 upward. Therefore, the support member 7 rotates counterclockwise in the figure around the hook rotation shaft 6, and the hook swinging arm 8 and the thread separating hook 10 move to the left in the figure integrally therewith. By this movement, the left / right swing transmission pin 11 provided on the hook swing arm 9 also moves to the left and separates from the hook swing cam 14. Here, since the left / right swing transmission pin 11 moves to a position where it does not come into contact with the large-diameter portion 14a of the hook swing cam 14, even if the hook swing cam 14 rotates in this state, it is necessary to perform thread separation. The rotational force is not transmitted to the hook 10 at all, and the thread separating hook 10 is kept stopped.
[0023]
For this reason, compared with the above-mentioned prior art (the technique described in Japanese Patent Application No. 5-157687), the thread separating hook 10 is always swung to the right or left regardless of whether or not the overlocking is performed. Wear and deterioration of movable members such as the moving arm 9, the right and left swing transmission pin 11, the hook swing cam 14, and the like are greatly reduced. In particular, since the overlock stitch is usually driven at a higher speed than the double chain stitch, the wear and deterioration of the movable member as described above are more likely to occur than the double chain stitch which requires the thread handling hook. This has been a common occurrence in overcast stitches that do not require thread handling hooks. Therefore, the life of each movable member of the present embodiment was significantly improved by eliminating wear and deterioration caused by overcasting.
[0024]
Further, in the overlock sewing in which the high-speed driving is performed, in the above-described prior art, the left and right swing transmission pins 11 jump due to the step between the large diameter portion 14a and the small diameter portion 14b of the hook swing cam 14, and a gap between the two members. In this embodiment, the noise problem can be solved, and the working environment can be improved.
Further, in order to prevent the empty ring formed in the overlock stitch from being locked to the thread separating hook 10, the thread separating hook 10 is also moved from the empty ring forming hole 3a in the present embodiment, similarly to the above-mentioned prior art. It is positioned rearward (see FIGS. 8A and 8B). However, in this embodiment, since the thread separating hook 10 is stopped, even if the empty ring contacts the thread separating member, the sewing machine cannot operate because the thread separating hook 10 does not forcibly wind the empty ring. There is no accident such as falling into the room or breaking the cloth.
[0025]
In the above embodiment, the switching lever 24 and the moving member 22 are always in contact with each other by urging the moving member 22 to the left by the tension spring 26, and the switching lever 24 is always held at the S2 position. As shown in FIG. 9, the moving member 32 and the switching lever 34 are connected by a connecting pin 32a inserted into the long hole 34a, and the moving member 22 is moved only by the operation force of the operator. You may make it do.
[0026]
Further, the contact member is not limited to one that presses the support member, and may be one that contacts the hook swinging arm 9 or the thread separating hook 10, and the shape and arrangement of the contact member can be appropriately changed as necessary. It is.
[0027]
Further, the left / right movement transmitting means in the above-described embodiment has the left / right swing transmission pin 11, the hook swing cam 14, and the like. However, the present invention can be implemented using other configurations. For example, the thread separating hook 10 and the like may be directly pressed by a cam that swings and rotates together with the lower looper shaft 13 without passing through the left and right swing transmission pins 11 and the like. Also, the selection means is not limited to the lever as described above, and a dial or the like, whose center is axially mounted and which performs a rotational movement, may be used, and this may be linked with the blocking means.
[0028]
In the above embodiment, an overlock sewing machine having two needles and four threads has been described as an example. The present invention is also applicable to an overlock sewing machine having one needle and two threads or one needle and three threads. However, the present invention is not particularly limited to the above embodiment.
[0029]
【The invention's effect】
As described above, the present invention provides a lower looper capable of swinging in the left-right direction and the front-rear direction in synchronization with the raising / lowering operation of the sewing needle, and a left-right direction and a front-rear direction associated with the swinging motion of the lower looper. In an overlock sewing machine including a swingable thread separating member and capable of selectively performing overlock sewing and other types of sewing such as double chain stitching or flat sewing, overlock sewing is selected. In this case, the blocking means blocks the transmission of the movement from the lower looper to the yarn separating member, so that unnecessary wear and deterioration of the yarn separating member and the movable member linked thereto can be prevented. Life can be greatly extended. In addition, since the thread separating member does not swing unnecessarily, it is possible to prevent an accident such as an empty ring from being entangled, thereby improving safety.
[Brief description of the drawings]
FIG. 1 is an external perspective view of an overlock sewing machine according to an embodiment of the present invention.
FIG. 2 is a partially enlarged perspective view of the embodiment.
FIG. 3 is an exploded perspective view of what is shown in FIG.
FIG. 4 is a side view showing a blocking means and the like in the embodiment.
FIG. 5 is a bottom view of what is shown in FIG.
FIG. 6 is a view showing a movement locus of a thread handling hook in the embodiment.
7A and 7B are diagrams showing a positional relationship among a lower looper, a thread handling member, a sewing needle and the like in the embodiment, FIG. 7A is a plan view showing a state where the sewing needle has reached a top dead center, and FIG. (C) is a plan view showing a state in which the lower looper has begun to move in the backward direction, and (d) is a side view of the thing shown in FIG. is there.
FIGS. 8A and 8B are diagrams showing a state of forming an empty ring and a position of a thread separating hook at the time of overcasting in the embodiment. FIG. 8A is a side view, and FIG. 8B is a plan view. ing.
9A and 9B are views showing a blocking means according to another embodiment of the present invention, wherein FIG. 9A is a side view and FIG. 9B is a plan view.
FIG. 10 is an explanatory perspective view showing a stitch formed by double chain stitching of two needles and three threads.
FIG. 11 is an explanatory perspective view showing a positional relationship between a needle thread, a lower looper, a looper thread, and a sewing needle in double chain stitching, and (a) shows a positional relationship when an appropriate stitch is formed; (B) shows a positional relationship when an appropriate stitch is not formed.
[Explanation of symbols]
N1, N2 sewing needle T1, T2 needle thread TL looper thread 24 switching lever (selection means)
4 Lower looper 3 Needle plate 10 Yarn handling hook (yarn handling member)
13 Lower Looper Shaft 15 Swing Transmission Arm 12 Front and Back Swing Transmission Pin 14 Hook Swing Cam 11 Left and Right Motion Transmission Pin 22 Moving Member 23 Contact Member

Claims (2)

Selecting means for selecting either one of the overlock stitching and the double chain stitch or the flat stitch, which is a sewing mode other than the overlock stitching;
When the sewing mode selected by the selection means is a sewing mode other than the overlock stitching, the front and rear swinging motion and the left and right swinging motion are simultaneously performed in synchronization with the lifting and lowering motion of the sewing needle, and the overlocking is performed. Sometimes a lower looper that performs a left and right swing motion in synchronization with the lifting and lowering of the sewing needle,
A thread separating member held swingably in the front-rear direction and the left-right direction;
Longitudinal movement transmitting means for transmitting the swinging movement of the lower looper in the longitudinal direction to the yarn separating member,
Right and left motion transmitting means for transmitting the swinging motion of the lower looper in the left and right direction to the yarn separating member,
At the time of selection other than the overlock stitching, the thread separating member performs a front-rear and left-right combined movement in synchronization with the front-rear and left-right combined movement of the lower looper, and the needle thread captured by the lower looper has a predetermined positional relationship with the sewing needle. In the overlock sewing machine, when the overlock sewing is selected by the sewing mode selecting means, the transmission of the swinging motion from the lower looper to the thread separating member performed by the left and right motion transmitting means is interrupted. An overlock sewing machine comprising means. The left and right motion transmitting means includes a lower looper shaft that performs a rotational swing motion together with the lower looper, a rotating cam fixed to the lower looper shaft so as to face the yarn separating member, and a thread separating member provided on a cam surface of the rotating cam. And a biasing means for biasing the thread cam so that the thread separating member abutting on the rotating cam swings right and left by rotation of the rotating cam,
The blocking means includes a moving member that advances and retreats with respect to the thread separating member in accordance with a selecting operation by the selecting means, and the moving member advances toward the thread separating member in accordance with the selecting operation of the overlock stitching. 2. The overlock sewing machine according to claim 1, wherein the thread separating member is separated from the rotary cam against the urging means, while the moving member retreats and retreats from the thread separating member in response to a selecting operation other than the overlock sewing. .

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