JPH0632731B2 - Sewing machine thread entanglement prevention device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thread entanglement prevention device for a sewing machine, which prevents thread entanglement during operation of the sewing machine after threading onto a slit type balance of the sewing machine.

(Prior Art) Conventionally, in order to facilitate threading on the balance of the sewing machine,
A slit is formed in the thread holding portion of the balance so that the upper thread can be easily hooked to the thread holding portion through the slit without releasing the hand from the upper thread. But,
In this case, when the balance is moved down after the yarn is delivered, there is a drawback that the loosened yarn may pass through the slit and come out of the yarn holding portion of the balance, or the yarn may be double entangled.

(Problems to be Solved by the Invention) As a preventive measure, for example, US Pat. No. 3,756,
As described in Japanese Patent No. 176, the shape of the slit communicating with the thread holding portion of the thread take-up is formed into a labyrinth shape, but in this case, even if the thread omission can be prevented to some extent, the thread entanglement is prevented. There was a drawback that I couldn't do it.

(Means for Solving the Problem) In view of the above-mentioned conventional problems, the present invention has a thread holding hole communicating with a thread insertion opening through a groove hole formed in a free end portion thereof within a predetermined movement range. In a sewing machine equipped with a slit balance that performs a yarn loosening motion and a yarn pick-up motion, the slit balance is bent downward so as to close the yarn insertion opening from the upper edge of the yarn insertion opening, and the bending thereof. An end is formed so as to extend to a position where the end closely faces one side surface of the slit balance, and a thread regulating member is fixed to the machine frame of the sewing machine. The slit balance extends between the yarn holding hole and the extending portion within the predetermined movement range in order to restrict the upper yarn held in the holding hole from moving toward the yarn insertion opening. Proximity to the side surface on which the extension is located To form a yarn regulating edges facing.

(Operation) In the thread entanglement prevention device of the sewing machine configured as described above, in the thread down state after the slit thread is moved up and the upper thread is unwound, the thread is unwound near the thread holding hole of the slit thread balance. When the upper thread moves in the thread insertion opening direction of the slit balance even if it becomes a loop shape, the loop-shaped upper thread is inserted on the side of the slit balance opposite to the extension side. The needle thread is prevented from coming off from the thread insertion opening by contacting the extending portion that closes the opening, and it is not possible to double entangle with the thread holding hole.

On the other hand, on the extension portion side of the slit balance, the loop-shaped upper thread is prevented from coming off from the thread insertion opening by contacting the thread regulation edge of the thread regulation member, and the thread holding It cannot be entangled in the hole twice.

(Embodiment) Next, a configuration of an embodiment of the present invention will be described with reference to the drawings.

Bed part that constitutes the machine frame of electronically controlled lockstitch sewing machine (11)
The pedestal portion (13) erected at the right end of (12) is provided with an arm portion (14) extending horizontally from the upper end to the left and facing above the bed portion (12). On the head (15) provided at the left end of the arm (14), the presser bar (16) is attached to the presser foot (1
The needle bar (19) is attached to the needle bar support (18) so that it can move up and down together with the sewing needle (20) at the lower end of the sewing machine. It is mounted so that it can be driven up and down by a main shaft (21) and can be driven to swing left and right around a pin (22) by a known swinging mechanism.

The sewing machine seed shaft (21) is rotatably supported by a machine frame via a bush metal (23) and the like, and an auxiliary shaft (24) and a main shaft (21) are diagonally above and behind the seed shaft (21). The swing lever (25) is rotatably mounted parallel to the machine frame, and one end of a swing lever (25) is rotatably mounted on the counter shaft (24). The crank pin (27) of the balance crank (26) extends to the left end surface side of the balance crank (26) fixed to the rocking lever (26).
Extend through the elongated cam hole (28) of (25) and swing lever (2
On the left side of 5), there is a connecting plate on the left end of the crank pin (27).
(29) is fixed, and the pin (3
The needle bar crank (31) is rotatably connected to (0), and the lower end of the needle bar crank (31) is connected to the middle part of the needle bar (19).

At the upper end of the front part of the rocking lever (25), a slit thread take-up body (32) extending upward in a crank shape, in this case, especially in the thread insertion opening (33), a slit-shaped slot is formed. Slit thread balance (32) having a thread holding hole (32B) communicating with (32A) at its free end is integrally formed, and the upper thread is moved within a predetermined range of motion.
Perform the relaxation motion and the thread pick-up motion of (34). As shown in FIG. 6, FIG. 7 and FIG.
An extension portion (35) bent downward is formed from the upper edge of the thread insertion opening (33) so as to close the thread insertion opening (33). The bent end of the extending portion (35) is extended to a position facing one side surface of the slit balance (32) closely.

As shown in FIGS. 2 and 3, the cam hole (28) of the swing lever (25) has the same radius as the rotation locus of the crank pin (27) and the crank pin (27) near the uppermost position. Is formed by an arc hole (37) that allows the rotation of about 74 ° and a short straight hole (38) extending straight from both ends of the arc hole (37). The outer peripheral portion of the cam hole (28) is reinforced. It is reinforced with the part (39).

The balance crank (26) and the crank pin (27) with the crank pin (27) inserted through the cam hole (28) of the swing lever (25).
Is rotated around the main shaft (21), the rocking lever (25)
4) With the crank pin (27) as a swing center, the crank pin (27) is driven to swing up and down vertically between the uppermost position shown by the solid line in FIG. 2 and the lowermost position not shown, and at this time, the sewing machine main shaft (21) The needle bar crank (31) and crank pin (27) are synchronized with the rotational movement.
The needle bar (19) is reciprocally driven up and down via the. The spindle (2
Immediately to the left of the leftmost needle bar crank (31) in (1), a plate member (40) that is a part of the machine frame is provided orthogonal to the main shaft (21). As shown in FIG. 2, at a position slightly forward of the main shaft (21), a pretensioning device (41) capable of giving passage resistance to the upper thread (34) is provided on the left side portion of the plate member (40) if necessary. Is provided.

This pre-tensioning device (41) allows the upper thread (34) to pass between a pair of thread tension discs (42), and the spring force can be adjusted by rotating the dial to adjust the thread passing resistance. I am doing it. Further, of the upper thread supply device from the thread spool (43) to the eye hole of the sewing needle (20) from the thread holding hole (34B) through the thread unwinding device (36) that operates in conjunction with the balance (32), Thread the upper thread (34) from the piece (43) to the thread holding hole (32B) of the balance (32) into the spindle (2
The following thread passing control device (44) is provided so that it can be restrained or released in synchronization with the movement of 1).

The plate member is located below the pretensioning device (41).
The thread guide plate (45) (thread engaging body) is fixed to the left side of (40),
A movable plate arranged near the left side surface of the thread guide plate (45)
(46) and the lower end of the link arm (47) are rotatably attached to the plate member (40) with stepped screws (48), and the movable wheel of the movable plate (46) is
(49) (thread engaging body) comes into contact with the regulating portion (50) of the yarn path regulating plate (45) from below and the needle thread (34) is provided between the regulating portion (50) and the movable wheel (49).
The movable plate (46) is elastically attached by a spring (51) fixed to the machine frame so that the movable wheel (49) of the movable plate (46) is brought into pressure contact with the regulating portion (50). Energized, arm of movable plate (46)
The contact wheel (53) at the upper end of (52) contacts the contact portion (54) near the lower end of the link arm (47) from the front.

As shown in FIGS. 2 and 5, an annular V groove (55) is formed on the peripheral surface of the movable wheel (49), and the regulating portion (50) of the yarn guide regulating plate (45) is formed.
Is formed in an inverted U shape in a side view so as to engage with the V groove (55) in the upper half of the movable wheel (49) from above, and the restricting portion (50) has a U-shaped cross section. Has been formed.

The needle thread (34) that has passed through the pretensioning device (41) is bent into a U-shape by the regulating portion (50) of the yarn path regulating plate (45), and the balance (3
It extends to the sewing needle (20) via the thread holding portion (35) of (2).

The movable wheel of the movable plate (46) is timed by the rotation of the main shaft (21).
In order to drive (49) up and down to release the upper thread (34) and restrain it at a predetermined timing, the main shaft (21) has an elliptical shape at a position corresponding to the right end side portion of the counter shaft (24). A rotary cam (57) having a cam groove (56) is fixed, and a contact (59) at the tip of the first arm (58) fixed to the counter shaft (24) engages with the cam groove (56). There is.

On the other hand, the second arm (60) is fixed to the left end of the counter shaft (24), and the lower end of the second arm (60) fits the pin (62) into the loose pin hole (61) of the link arm (47). Are linked together.

As shown in FIGS. 6 and 7, a thread restricting member (63) is fixed to the machine frame of the sewing machine (11). This thread regulating member
In (63), among the both side surfaces of the slit balance (32), which extends between the thread holding hole (32B) and the extension portion (35) within a predetermined movement range of the slit balance (32). A thread regulating edge (64) is formed so as to closely face the side surface where the extending portion (35) is located.

The thread regulating edge (64) contacts the upper thread (34) when the upper thread (34) held in the thread holding hole (32B) moves toward the thread insertion opening (33). No more needle thread (3
The movement of 4) is regulated.

The extending portion (35) of the slit balance (32) and the thread restricting member (63) having the thread restricting edge (64) constitute a thread entanglement preventing device of the sewing machine.

Next, the operation of this embodiment will be described.

In the sewing machine (11) provided with the sewing machine thread entanglement prevention device (65) configured as described above, the balance (32) is moved upward to move the upper thread (34).
In the lower state of the balance (32) after being fed, the upper thread (34) fed near the thread holding hole (32B) of the balance (32) becomes a loop, When the free end moves in the direction of the thread insertion opening (33), the looped upper thread (34) closes the thread insertion opening (33) on the opposite side of the extension (35) of the balance (32). The thread holding hole (32B) as well as the thread holding hole (32B) coming into contact with the extending portion (35) on the opposite side of the loop, and coming off the thread insertion opening (33).
I can't do double entanglement.

On the other hand, on the extension portion (35) side of the balance (32), the loop-shaped upper thread (34) moves along the extension portion (35) closing the thread insertion opening (33), In this case, the thread can be removed from the thread insertion opening (33) or double entangled with the thread holding hole (32B), but in this case, the thread insertion opening of the upper thread (34) held in the thread holding hole (32B).
Since the yarn restricting member (63) having the yarn restricting edge (64) that restricts the movement toward the (33) is arranged close to the side surface where the extending portion (35) is located, a loop shape is formed. The upper thread (34) contacts the thread regulating edge (64) of the thread regulating member (63), and the thread inserting opening (3
Of course, it cannot be pulled out of 3), nor can it be twined in the yarn holding hole 32B.

(Effects of the Invention) As described above, according to the present invention, the extension part that closes the thread insertion opening is provided on the side opposite to the side where the extension part is provided, on both sides of the slit balance. This makes it possible to reliably prevent the upper thread from slipping off, and to reliably prevent the looped upper thread from being double entangled in the thread holding hole.

Furthermore, on the side where the extension portion of the slit balance is provided, by restricting the movement of the upper thread by the thread regulating edge of the thread regulating member, it is possible to prevent the upper thread from coming off from the thread insertion opening. Therefore, it is possible to reliably prevent the looped upper thread from being double entangled in the thread holding hole.

[Brief description of drawings]

FIG. 1 is a perspective view showing an entire embodiment of the present invention, FIG. 2 is a perspective view of an essential part thereof, FIG.
Figures and 5 are detailed views of the main parts, and Figure 6 is a thread regulating member (63).
7 is an enlarged left side view showing the arrangement of the slit balance (32) and the slit balance (32).
6 is a plan view of FIG. 6 showing the thread regulating member (63) in a cross section, and FIG. 8 is an enlarged front view of the portion (32) of the balance. (11) …… Sewing machine, (32) …… Slit balance (32A) …… Slot hole, (32B) …… Thread holding hole (33) …… Thread insertion opening, (34) …… Upper thread (35)… … Extending part, (63) …… Thread regulating member (64) …… Thread regulating edge, (65) …… Thread entanglement prevention device

Claims (1)

[Claims] 1. A thread holding hole (32B) communicating with a thread insertion opening (33) through a slot (32A) is provided at a free end portion thereof, and a thread relaxing motion and a thread take-up motion within a predetermined motion range. Slit balance to exercise
In the sewing machine provided with (32), the slit balance (32) is bent downward from the upper edge of the thread insertion opening (33) so as to close the thread insertion opening (33) and the bending thereof. An extension portion (35) whose end is extended to a position facing one side of the slit balance (32) in close proximity.
A thread regulating member (63) is fixed to the machine frame of the sewing machine, and the upper thread (34) held in the thread holding hole (32B) is attached to the thread regulating member (63). In order to restrict the movement toward the insertion opening (33), the thread holding hole (32
B) and the extension part (35) and extends between the slit balance (3
A thread entanglement prevention device for a sewing machine, characterized in that a thread regulating edge (64) is formed in close proximity to a side surface of the both side surfaces of the extending portion (35) of the side surface (2).