JP2791281B2 - Chain stitch sewing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention allows a looper to be removably rotated from a sewing position to a threading position in order to thread a looper connected to a looper shaft. It relates to a chain stitch sewing machine.

[0002]

2. Description of the Related Art Generally, in a sewing machine in which a seam is formed with a looper of this type, when a thread is threaded, a main shaft puller is used.
The looper is manually rotated to swing the looper to a position suitable for threading within the sewing range, and then the looper thread is passed through the looper with tweezers or the like. However, at the sewing position below the needle plate,
Even when the pawl was swung, there was not enough space around the looper, and much time was required for the looper threading operation.

In order to solve such a problem, conventionally,
As shown in Japanese Utility Model Publication No. 60-21004,
A member has been proposed in which a member for swinging the papper shaft has a cam surface, and the looper arm can be turned between a sewing position and a threading position by an eccentric pin engaged with the cam surface.

[0004]

However, in the conventional apparatus in which the looper arm can be freely turned, the connection between the looper arm and the swinging member that gives the swinging motion to the looper arm is not reliable. When a high-speed sewing operation or an impact load was applied to the looper, the connection between the looper arm and the swinging member was lost, and the formation of the seam was adversely affected.

After the threading operation is completed, the cloth base covering the lower part of the needle plate is closed. The needle will also be sewn. SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has been described in terms of engagement between a looper mounting arm, a detachable lever, and a swing member. An object of the present invention is to provide a chain stitch sewing machine which is excellent in operability of detachment, more reliably engages during sewing, and can automatically return a looper to a sewing position after threading.

[0006]

According to the present invention, there is provided a swing member (8) which is connected to the looper driving means and swings in synchronization with the vertical movement of a sewing needle. A looper mounting arm (6) rotatably supported at one end by the swinging member, and a looper at the other end; and a detachable mounting mechanism having a central portion supported by the looper mounting arm. A lever (16) is provided between the detachable lever and the looper mounting arm. A detachable locking means, and a first urging member having one end locked to the looper mounting arm and the other end locked to the detachable lever, and for urging the detachable lever to engage with the swinging member. Means (20).

Further, the detachable lever and the swing member are fixed to the sewing machine frame except for the lower stop position of the sewing needle in the looper swing range of the sewing position. A restriction means (24) for restricting departure from the state may be provided. Further, the second end is locked to the looper mounting arm at one end and the swinging member at the other end, and constantly biases the looper mounting arm in the direction in which the locking means is engaged. Urging means (21)
May be provided.

According to a fourth aspect of the present invention, the looper is covered with a needle plate, and a cloth base (25) is provided on the sewing machine frame so as to be openable and closable. Moving means (25, 26) may be provided that, when closed, engages the operating portion of the detachable lever at the threading position and automatically moves the looper to the sewing position.

Further, a switching means (27, 28, 6e) capable of changing the urging force of the first urging means may be provided.

[0010]

According to the present invention, by pressing the detachable lever, the space between the swinging member and the detachable lever and the looper mounting arm is changed from the engaged state (holding state) to the detached state (disengaged state). .
Then, the looper mounting arm holding the looper is rotated with respect to the swinging member, and the looper is moved from the sewing position to the threading position. Thereafter, the pressing of the detachable lever is stopped, the looper is held (engaged) at the threading position, and threading is performed. Next, the swing member and the detachable lever are detached, rotated,
The sewing machine is held, the looper is returned to the sewing position, and sewing is performed.

After the threading operation is completed, the looper mounting arm automatically returns to the sewing position by closing the cloth table even if the looper mounting arm is held at the threading position. That is, the protrusion provided on the cloth base presses the detachable lever,
The connection between the detachable lever and the swinging member is released. Since the looper mounting arm is urged in the sewing position direction by the second urging means, the looper rotates in the threading position and is held at the threading position. At this time, the detachable lever is urged by the first urging means in the direction in which the detachable lever is engaged with the swing member, so that the connection between the swing body, the detachable lever and the looper mounting arm is more secure, and sewing is performed. There is no backlash in the looper.

Further, in the swing range of the looper during sewing, a regulating means is provided in order to prevent the swing member and the detachable lever from being disengaged from the engaged state. Further, when the looper is at the sewing position, the biasing force is increased by using the switching means for switching the biasing force of the first biasing means, and the holding state of the detachable lever and the swinging member is more reliably maintained. Or when moving to the threading position, reduce the urging force.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a chain stitch machine according to the present invention will be described below with reference to the drawings. FIG. 1 is a front view of a main part of a first embodiment of the present invention. FIG. 2 is a left side view thereof. FIG. 3 is an explanatory view showing rotation of the looper to a sewing position and a threading position in the first embodiment, and automatic return by opening and closing of the cloth base.

In the figure, reference numeral 1 denotes a sewing needle which moves up and down in conjunction with the main shaft of the sewing machine, and a needle plate 2 through which the sewing needle 1 is inserted is provided below the sewing needle. Reference numeral 3 denotes a looper, which is located below the needle plate 2 and which receives a looper thread 5 through a thread guide 3a.
b. A seam is formed by knotting the looper thread 5 and the upper thread 4 passed through the needle hole of the sewing needle 1. Reference numeral 10 denotes a looper driving means for swinging the looper 3 in synchronization with the vertical movement of the sewing needle 1. The looper driving means 10 includes a rotating shaft 13 rotatably supported by the sewing machine frame 12 and a main motor (not shown) for swinging the rotating shaft 13.

Reference numeral 8 denotes a swinging member, one end of which is fixed to the rotating shaft 13 of the looper driving means by a bolt 14, and the other end of which is provided with a shaft 9 by a bolt 15. The outer peripheral portion 8a of the swinging member 8 is a cam surface having two engaging concave portions 8aa and 8ab. Reference numeral 6 denotes a looper mounting arm, one end of which is pivotally supported by a shaft 9 projecting from the swinging member 8 and the other end of which is formed by a holding portion 6a for fixing the looper 3 with screws 7.

Reference numeral 16 denotes a detachable lever, which is rotatably supported by the looper mounting arm 6 by a pivot pin 17 projecting from the center. The upper portion 16a is an operation portion, and the lower portion 16b on the opposite side holds the engagement shaft 18. The engagement shaft 18 and the cam surface 8aa of the swing member 8 constitute a locking means. Then, the engaging shaft 18 is engaged with the engaging concave portion 8aa or 8ab of the cam surface 8a of the swing member 8, and is locked by the swing member 8. A projection 1 is provided at the center of the detachable lever 16.
9 are protruded.

Reference numeral 20 denotes a tension spring (first urging means) as an embodiment of the urging means. The looper holding part has one end located on the projection 19 and the other end located in the vertical direction of the projection 19. 6a
Is locked. The tension spring 20 is always attached and detached lever-1.
6 is urged in a counterclockwise direction with the rotation pin 17 as the center of rotation. As a result, the detachable shaft 18 of the detachable lever 16 is
Unless an external force is applied to the operation unit 16a in the X direction in the figure,
The engagement shaft 18 maintains the state of being locked in the engagement recess of the swinging member 8. (Holding state) Reference numeral 21 denotes a helical spring (second urging means) as an embodiment of the urging means, which is supported by the shaft 9. And one end is
The other end is fixed to a projection 22 provided on the mounting arm 6, and the other end is fixed to a projection 23 provided on the swinging member 8. The helical spring 21 urges the looper mounting arm 6 supported by the shaft 9 in a clockwise direction.

The attachment / detachment lever 16 has a tension spring 20 with a rotation pin 17 pivotally supported by the looper mounting arm 6 as a rotation center.
Urged in the counterclockwise direction. On the other hand, the looper mounting arm 6 is urged clockwise by the helical spring 21. At this time, the force acting on the detachable lever 16 is set such that the force for rotating the detachable lever 16 in the counterclockwise direction is increased by a predetermined amount. Therefore, the detachable lever 16 and the swing member 8 are urged so as to maintain the engaged state.

Reference numeral 24 denotes a regulating member for regulating the engagement between the detachable lever 16 and the cam surface 8a of the swing member 8. Regulator 24
Is fixed to the sewing machine frame 12. And the regulating member 24
Except for the lower stop position of the sewing needle 1 in the normal sewing position, that is, the position where the looper performs the upper thread capturing movement in response to the vertical movement of the sewing needle (FIG. 3-S), the engagement shaft The upper surface of the engagement shaft 18 is covered so as to prevent the separation of the rocking member 18 from the concave portion 8aa of the cam surface 8a of the rocking body.

Reference numeral 25 denotes a cloth base, which is pivotally supported by a shaft (not shown) provided on the rear side in the sewing direction in the vertical direction of the sewing machine frame. Its free end can open and close the sewing machine needle plate lower part in the left-right direction. The cloth base 25 is provided with a protrusion 26. When the cloth base is closed with the looper mounting arm 6 held at the threading position, the protrusion 26 also moves. With the operation unit 16a. Thereby, the detachable lever 16 is rotated clockwise so as to disengage the engagement between the oscillator cam surface 8ab and the engagement shaft 18.

The operation of the present invention will be described based on the above configuration. When sewing the sewing machine, as shown in FIG.
6 is fixed to the cam surface recess 8aa of the rocking body.
Is fitted. Tension spring 20 (first biasing means)
As a result, the engagement shaft 18 receives a moment in a direction (FIG. 1W direction) in which the engagement shaft 18 engages with the concave portion of the cam surface of the rocking body 8. The engaging shaft 18 is securely engaged with the concave portion of the cam surface at the time of sewing, and the swinging body 8, the detachable lever 16, the engaging shaft 18 and the looper mounting arm 6 are integrally connected and held. keep. Accordingly, a swinging motion, that is, a needle thread catching motion is imparted to the looper via the swinging member 8 and the looper mounting arm 6 from the looper driving means which swings in synchronization with the vertical movement of the sewing needle. .

To thread the looper 2, first, the rotation of the main motor is stopped, and the sewing needle is stopped at the lower stop position. Next, the free end of the cloth base 25 covering the lower part of the needle plate is rotated leftward to open. Next, the engagement between the engaging shaft 18 and the cam surface concave portion 8aa of the rocking body 8 (the locking means) is released. That is, when the operating portion 16a of the detachable lever 16 is pressed in the X direction in FIG. 1 against the spring pressure of the extension spring 20, the detachable lever 16 rotates clockwise. Then, when it is rotated downward (counterclockwise) along the cam surface 8a of the rocking body 8 against the elastic force of the spring 21 as the second urging means, the looper mounting arm 6, Looper 3 is also counterclockwise (FIG. 3).
-T direction). When further rotated, the engagement shaft 1
8 is a recess 8ab formed by the flange 15 and the oscillating body.
Engages. After the engagement, when the load on the detachable lever 16 is removed, the looper is locked at the threading position by the first urging means as shown in FIG. Since the threading position has a sufficient space around the looper, the threading operation is easy.

After the looper threading is completed, when the engagement of the engagement shaft 18 is released by the same operation procedure as described above, the looper mounting arm 6 is pivoted by the spring 21 as the second urging means. 9 rotates clockwise. In connection with this, the engaging shaft 18 moves the cam surface engaging recess through the detachable lever 16 from 8ab to 8a.
a (in the direction of FIG. 3-U), and lock the looper at the sewing position. Thereafter, the cloth table 25 is rotated rightward and closed, and the preparation for sewing is completed.

At this time, even if the user forgets to change the looper 3 from the threading position to the sewing position, when the cloth base 25 is closed, the projection 26 provided on the cloth base will cause the operating part 1 of the detachable lever 16 to operate.
6a. Then, the lock between the oscillating body cam surface 8ab and the engagement shaft 18 is released, and the looper mounting arm 6 is rotated clockwise about the shaft 9 by the spring 21 as the second urging means. Accordingly, the engaging shaft 18 is connected via the detachable lever 16.
Moves the cam surface engaging recess from 8ab to 8aa (in the direction of FIG. 3-U) and locks the looper at the sewing position.

Therefore, when the cloth stand 25 is closed, the looper at the threading position is automatically rotated to the sewing position. Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 4 is a front view of a second embodiment of the present invention. The second embodiment is characterized in that switching means for changing the urging force of the first urging means 20 of the first embodiment is provided.

Reference numeral 6 denotes a looper mounting arm having an inverted L-shaped groove 6e. The adjuster 27 can move along the L-shaped groove 6e, and is locked at both ends 6c and 6d of the groove. 28
Is a protruding portion, which protrudes from the center of the detachable lever 16 and has a groove 28a in the horizontal direction. The pin 29 can move freely along the groove 28a. Extension spring 20
Is locked at one end to the adjuster 27 and at the other end to the pin 29.
For this reason, the detachable lever 16 is moved by the tension spring 20.
It is urged in a counterclockwise direction with the rotation pin 17 as the center of rotation. This urging force (first urging force) changes when the locking position of the adjusting body 27 is changed.

The operation of the second embodiment will be described. Since the adjusting body 27 is locked at the groove end 6c at the sewing position,
Since the urging force is large, the swing member 8 and the detachable lever 16
The connection (locking) between the arm and the looper mounting arm 6 is secure. When the looper mounting arm is rotated from the sewing position to the threading position, first, the adjusting body is moved from the groove ends 6c to 6d, whereby the urging force of the looper mounting arm is reduced. Next, the looper is rotated to the threading position to perform threading. After the completion of the threading, the detachable lever 16 is rotated to return to the sewing position. Thereafter, the adjuster 27 is moved from 6d to 6c along the groove 6e. Accordingly, since the urging force of the tension spring 20 is increased, the connection between the swinging member, the detachable lever and the looper mounting arm is surely performed during sewing. On the other hand, when performing the threading operation, the adjusting body 27 is moved to reduce the urging force.
The holding state of the swing member 16 and the swing member 8 can be easily separated.

As described above, the first biasing force can be changed by moving the adjusting body, so that the locking (holding) between the swinging member 8 and the detachable lever 16 is more secure than during sewing, and is easy during threading operation. The lock can be released. The present invention is not limited to the first and second embodiments. For example, as shown in FIG. 5, the detachable lever 16 includes two detachable shafts 18a and 18b and a swing member provided at three engagement recesses 8aa. , 8ab, and 8ac to easily secure locking (holding). Further, the shape of the engaging concave portion of the swing member is not limited to the U-shape as shown in FIG. 1, but may be various shapes such as an L-shape.

Further, in the present invention, the engaging recess is provided on the swinging member and the engaging shaft is provided on the detachable lever. On the contrary, the engaging shaft is provided on the swinging member and the engaging recess is provided on the detachable lever. It is easy to think about it. Further, the looper threading position of the present invention is located in the direction rotated counterclockwise with respect to the sewing position, but it is easily conceivable to provide the threading position at the position rotated clockwise.

[0030]

According to the present invention, the looper can be easily rotated from the sewing position to the threading position having a space around the looper, thereby facilitating the threading operation. Further, since the lock of the looper mounting arm, the detachable lever, and the rocking body at the sewing position is ensured, the looper does not rattle during sewing.

Further, by using the restricting means for restricting the detachment of the swinging member and the detachable lever, the engagement between the swinging member and the detachable lever can be ensured during sewing, and the locking means can be used. Detachment from the engaged state can be prevented. Also, as in claim 3,
When the second urging means is used, the rotation from the threading position to the sewing position can be automatically performed.

Further, if the moving means is used, the looper is automatically returned to the sewing position when the cloth table is closed, even if the looper is returned to the sewing position after the threading operation is completed. Since the sewing position is returned to the sewing position, a stitch is reliably formed even when sewing is started. Further, when the switching means is used, the engagement is more secure at the sewing position, and the lock can be easily released during the threading operation.

[Brief description of the drawings]

FIG. 1 is a front view of a main part according to a first embodiment of the present invention.

FIG. 2 is a left side view of the first embodiment.

FIG. 3 is an explanatory view showing rotation of a looper to a sewing position and a threading position in the first embodiment, and automatic return by opening and closing of a cloth base.

FIG. 4 is a front view of a main part according to a second embodiment of the present invention.

FIG. 5 is a front view of a main part of a third embodiment of the present invention.

[Explanation of symbols]

 1----------------------------------------------------------------------swinging member 6------------------------------------------- -Looper mounting arm 8aa --- --- Cam surface engaging recess (locking means) 18 --- --- Engaging shaft (locking means) 16 --- --- Detachable lever 20- −−−−− Tension spring (first urging means) 21 −−−−−− Twisted spring (second urging means) 24 −−−−−− Regulator (restrictor) 25 −−−− −−− Cloth base 26 −−−−−− Protrusion (moving means) 27 −−−−−− Adjustment body (switching means) 28 −−−−−−− Protrusion (switching means)

Claims (5)

(57) [Claims] A sewing needle which moves up and down in conjunction with a main shaft of a sewing machine; a looper which is located below a needle plate and holds a looper thread in a thread hole thereof; A looper driving means (10) for swinging the looper in synchronization with movement; a loop stitch for forming a seam by knotting the looper thread with a needle thread passed through the needle hole of the sewing needle. A swinging member (8) connected to the looper driving means and swinging in synchronization with a vertical movement of a sewing needle; one end of the swinging member is rotatably supported by the swinging member; Niru
A looper mounting arm (6) for holding a pallet, a detachable lever (16) having a central portion supported by the looper mounting arm and having an operation portion at one end; Provided between the arm and the mounting arm. A locking means capable of being detached freely, a first end having one end locked to the looper mounting arm and the other end locked to the detachable lever, and urging the detachable lever in a direction in which the locking means is engaged. Biasing means (20), and by pressing the operating portion of the detachable lever, the engagement of the locking means is released, and the looper mounting arm is moved to the sewing position and the threading position. A chain stitch sewing machine characterized by being rotatable. 2. A restricting means (24) fixed to the sewing machine frame and restricting the locking means from being disengaged from the engaged state except in the lower stop position of the sewing needle in the looper swing range of the sewing position. The chain stitch sewing machine according to claim 1, further comprising: 3. A second biasing means, one end of which is locked to the looper mounting arm and the other end of which is locked to the swinging member, and which constantly biases the looper mounting arm in a direction in which the locking means is engaged. The chain stitch machine according to claim 1, further comprising (21). 4. A cloth base (25) which covers the looper together with a needle plate, and is provided on the sewing machine frame so as to be openable and closable, and a projection is provided on the cloth base. Moving means (25, 25) for engaging the operating portion of the detachable lever at the through position and automatically moving the looper to the sewing position.
The chain stitch sewing machine according to claim 1, wherein 26) is provided. 5. The chain stitch sewing machine according to claim 1, further comprising switching means (27, 28, 6e) capable of changing the urging force of said first urging means.