JP2709472B2 - sewing machine - Google Patents

Description

The present invention relates to a sewing machine.

[Conventional technology]

As shown in Japanese Utility Model Application Laid-Open No. 58-181384, a fixed blade and a movable blade for bobbin thread cutting are arranged below the needle plate, and after elastically contacting the lower surface of the movable blade, cutting is performed. A thread holding body adapted to hold a cut end of a lower thread is fixed to a machine frame, and the elastic contact force of the thread holding body against a movable blade is adjusted by a pressure adjuster and a pressure adjusting screw. Have been.

[Problems to be solved by the invention]

In this conventional sewing machine, when the abutment force of the thread holding body against the movable blade is increased to secure the lower thread, the sewing machine starts to sew the lower thread from the part sewn to the cloth and the thread holding body from around a few stitches after sewing starts. There is a problem in that the cloth is in a tension state due to the movement of the cloth due to the movement of the cloth, and the movement of the cloth is hindered, the sewing pattern collapses, and the cloth is wrinkled. Also, if the contact force of the thread holding body against the movable blade is weakened to solve the above problem, when the shuttle rotates at the start of sewing and the blade of the shuttle removes the lower thread, the lower thread comes into contact with the movable blade. There has been a problem that the lower thread cannot be entangled with the upper thread because the thread comes off from the thread holding body, resulting in stitch skipping.
The present invention has been made in view of the above points, and its purpose is to ensure that the lower thread can be entangled with the upper thread at the start of sewing, and the cloth is moved when the cloth is moved by the start of sewing. An object of the present invention is to provide a sewing machine that can be freely moved.

[Means for solving the problem]

According to the present invention, a needle for lower thread feeding is rotatably provided below the needle plate, and a needle for upper needle feeding is provided above and below the needle plate so as to be vertically movable, and the needle is moved up and down. In a sewing machine, the cloth placed on the needle plate is sewn with the upper thread and the lower thread by rotating the shuttle together with
A fixed blade is disposed on the side of the lower thread passage locus between the needle plate and the shuttle below the needle plate, and the fixed blade is cooperated with the fixed blade to cut the lower thread. The movable blade is configured to freely reciprocate beyond the lower thread passage trajectory from the cutting position where the fixed blade is located. And a thread catching portion for cutting the middle of the lower thread between the cloth and the shuttle between the fixed blade at the cutting position and the cutting position. In the vicinity of the movable blade to be positioned at a position, a thread holding body having a free end pressed against the movable blade at the cutting position so as to be able to clamp the lower end free end side of the cut lower thread on the shuttle side. The thread holding body is provided with a pressing force against the lower thread on the hook side sandwiched between the movable blade and the thread holding body. In conjunction with the rotation is reduced after at least one or more stitches are formed at the annexed means loosened to easily removed the lower yarn.

[Action]

When the movable blade is reciprocated after the sewing of one place is completed, the movable blade hooks the lower thread located on the lower thread passage locus and cuts the lower thread between the fixed blade and the shuttle after the cutting. Is securely clamped between the movable blade and the thread holder. When sewing is started again at the next sewing position, the blade of the shuttle removes the bobbin thread, but since the cut end of the bobbin thread is securely clamped between the movable blade and the thread holder, the bobbin thread No omission occurs. As a result, reliable entanglement of the lower thread and the upper thread can be achieved. When the cloth is moved with the progress of sewing, the holding force of the thread holding body against the movable blade is reduced by the loosening means, whereby the holding of the lower thread can be released. As a result, the cloth can be moved freely.

〔Example〕

Hereinafter, drawings showing an embodiment of the present application will be described. First
In FIGS. 3 to 3, reference numeral 1 denotes a bed of the sewing machine. Reference numeral 2 denotes a needle plate provided on the bed 1 and has a needle drop hole 2a. Reference numeral 3 denotes a well-known shuttle for feeding a bobbin thread located below the needle plate 2, which is fastened as shown in FIG. Reference numeral 4 denotes a blade in the shuttle 3. Reference numeral 5 denotes a needle attached to a needle bar provided on a head (not shown) established on the bed 1, which is vertically movable so that it can pass through the needle drop hole 2a.

Numeral 8 denotes a lower thread cutting device provided on the lower side of the bed 1, in which reference numeral 9 denotes a support bracket fixed to the bed 1, which has a fixed blade mounting portion 9a and a movable blade support portion 9b. Reference numeral 10 denotes a fixed blade fixed to the fixed blade mounting portion 9a by a mounting screw 11, and as shown in FIG. 3, the lower thread passing locus A between the needle plate 2 and the shuttle 3 below the needle plate 2 It is arranged on the side. The fixed blade 10 has a cutting edge 12 at a lower edge portion on the lower thread passage locus A side. Reference numeral 13 denotes a movable blade provided movably with respect to the fixed blade 10. The base portion is fixed to an upper end portion of a support shaft 14 rotatably supported by the movable blade support portion 9b. In the figure, reciprocation is possible between a cutting position indicated by a solid line and a hooking rotation position indicated by a virtual line. In the movable blade 13, a thread wiper 15 is formed in an arc shape in which the distance from the rotation center decreases as going from the cutting position to the hooking rotation position, and the lower thread is rotated by the rotation of the movable blade 13. It is provided at a position where it moves across the passage locus A. Reference numeral 17 denotes a cutting edge, which has a hole edge above a through hole 16 formed in the movable blade 13. The blade edge 17 is moved by the rotation of the movable blade 13,
Is provided at a position where the lower side of the cutting edge 12 slides and moves. Numeral 18 denotes a thread hooking portion, which is provided at a position where the movable blade 13 moves across the lower thread passage locus A by rotation.

Next, reference numeral 20 denotes a movable blade operating device in the lower thread cutting device 8, in which 21 is a lever having an original portion fixed to a lower end portion of the support shaft 14, and 22 is a distal end portion of the lever 21. The connecting body is rotatably mounted and has a through hole 22a. Two
Reference numeral 3 denotes an operating rod which is inserted into the through hole 22a and is fixed to the connecting member 22 by a set screw 24, and is reciprocated a predetermined amount in the longitudinal direction by a driving device (not shown).

Next, 25 is a lower thread holding device. In the yarn holder 26 in this case, reference numeral 27 denotes a yarn holding receiver, which is constituted by the lower surface of the distal end portion of the movable blade 13 at the cutting position. Reference numeral 28 denotes a thread holding body, the base of which is fixed to one end of a support shaft 29 rotatably supported on the bed 1, and the free end of which is disposed so as to be able to press against the thread holding receiver 27. The thread holding member 28 is formed of a metal plate having a spring property, and its tip is bent obliquely downward. Reference numeral 30 denotes a thread holding body operating device in the thread holding device 25, which is a contact means for elastically contacting the free end of the thread holding body 28 with the thread holding receiver 27, and a pressing force of the free end against the thread holding receiver 27. It is designed to perform both functions as a loosening means for reducing (including zeroing). In the upper raw silk holder operating device 30, 31 is a swing arm fixed to the other end of the support shaft 29, 32 is a push solenoid, and its own solenoid body 32a is fixed to the bed 1 via a bracket 33. And
The plunger 32b is pin-connected to the tip of the swing arm 31. Numeral 34 denotes return springs fitted to the support shaft 29, one end of which is locked to the bed 1 and the other end of which is locked to the swing arm 31, and biases the swing arm 31 in a direction to retract the plunger 32b. ing. 35
Is a first stopper implanted in the bed 1, 36 is a second stopper implanted in the bed 1, and 37 is a third stopper for receiving the free end of the thread holder 28 as shown in FIG. The stopper is a part of the support bracket 9.

The operation of the above configuration will be described in chronological order. When sewing on the cloth N, the cloth N is placed on the needle plate 2 and the sewing machine is operated. In this case, the needle 5 moves up and down and the shuttle 3 rotates synchronously. In the process, the needle 5 guides the upper thread b below the cloth N. The upper thread “b” is entangled with the lower thread “a” fed out by the well-known action of the shuttle 3. After that, needle 5 again
Guides the upper thread b above the cloth N. This operation is sequentially repeated, and sewing is performed in a state where the upper thread b and the lower thread a form stitches at a predetermined interval on the cloth N as shown in FIG.

Next, after the completion of the sewing, the operating device of the thread holding device 25 is operated.
30 operates, and then the lower thread a is cut by the lower thread cutting device 8. That is, first, power is supplied to the push solenoid 32 of the thread holder operating device 30, and the plunger 32b projects to swing the arm 31.
Is pivoted to a position where it comes into contact with the first stopper 35, whereby the thread holding body 28 is rotated and its free end elastically contacts the thread holding receiver 27 of the movable blade 13. Next, the operating rod 23 of the movable blade operating device 20 moves forward in the longitudinal direction, and the lever 21 swings (forwards) from the position indicated by the solid line in FIG. 2 to the position indicated by the virtual line.
By the swing of the lever 21, the movable blade 13 swings (forwards) from the cutting position shown by the solid line in FIG. 3 to the hooking rotation position shown by the virtual line. In this process, the thread wiping unit 15 of the movable blade 13 moves across the lower thread passage locus A by sweeping the lower thread a located on the locus A. As a result, when the movable blade 13 reaches the hooking rotation position, the lower thread a is in a state of being located on the side of the thread hooking portion 18 of the movable blade 13. Next, the operating rod 23 moves back and the lever 21
Comes back. Due to this return movement, the movable blade 13 swings (returns) to the original cutting position. In the process, the thread hook 18 of the movable blade 13
Hooks the lower thread a and guides it to the fixed blade 10 side. Then, as shown in FIG. 5, the thread holder 27 engages with the thread holder 28 to slightly push down the thread holder 28 to hold the thread. The free end of the body 28
27, the cut end a 'of the lower thread a is sandwiched between them. Next, between the cutting edge 17 of the movable blade 13 and the cutting edge 12 of the fixed blade 10, an intermediate portion of the lower thread a between the cloth N and the shuttle 3 is cut as shown in the figure. In this cut state, the lower thread connected to the cloth N is shorter than the lower thread a connected to the shuttle 3. The extremely short bobbin thread a 'at the end connected to the shuttle 3 after the cutting is securely held between the thread holding body 28 and the thread holding receiver 27 as shown in FIGS. Up to. FIG. 6 shows a case where the length L from the holding position of the lower thread a to the end is about 7 to 8 mm.

After cutting the lower thread a, the cloth N on the needle plate 2 is freely moved to bring the next sewing place to the needle drop position.

Next, sewing is started again at the next sewing place. In this case, first, as shown in FIG. 12A, the needle 5 is lowered and the shuttle 3 is rotated, and the rotation of the shuttle 3 causes the blades 4 of the shuttle 3 to move between the shuttle 3 and the portion held by the thread holder 28. The transferred lower thread a is about 5 mm, as shown in FIGS. 8 and 9, and the end a 'of the lower thread a is connected to the thread holder 27 and the thread holder.
28, it is securely held between them, so that it can be prevented from coming off. In this state, the needle 5 penetrates the cloth N and guides the upper thread b downward (FIG. 12B). In addition, by the rotation of the shuttle 3, a well-known action of tangling the guided upper thread b and the lower thread a of the shuttle 3 is performed. In this case, even if the lower thread a is short, its end is held by the lower thread holding device 25 to prevent the thread from coming off.
Entanglement is reliably achieved. Thereafter, the needle 5 is raised (twelfth
Then, the upper thread b is guided above the cloth N as shown in FIG. 10, and the formation of the first stitch c on the cloth N is completed by the upper thread b and the lower thread a.

Thereafter, the cloth N on the needle plate 2 is moved a predetermined amount (for example, about 0.7 mm) to the left in FIG. 10, the needle 5 is lowered again (FIG. 12 d), and the rotation of the shuttle 3 is continued. Eleventh
As shown in the figure, the second stitch is formed (FIG. 12E).

Next, when the needle 5 is lowered for the third time as shown in FIG. 12, the power supply to the push solenoid 32 of the thread holder operating device 30 is stopped, whereby the swing arm 31 is moved to the second stopper 36. The thread holding member 28 is swung by the force of the return spring 34 to a position where it comes into contact with the thread holding member 28, and is rotated to the thread holding release position as shown in FIG. 11, and its free end is separated from the thread holding receiver 27 (FIG. 12). (G) together with the third stopper 37 to be supported. As a result, the cut end a 'of the lower thread a connected to the cloth N is
The hook is released from the space between the thread holding support 28 and the thread holding receiver 27 to be released. Therefore, after this, even if the cloth N is sequentially moved by the continuation of the sewing, the lower thread a connected to the first seam to the cloth N
Can be prevented from being pulled, and the movement of the cloth N is free, so that it is possible to prevent collapse of the sewing pattern and generation of wrinkles on the cloth N. It should be noted that the power supply to the push solenoid 32 is stopped during the period of h in FIG.
It may be performed after one or more stitches are formed.

In the present application, the thread holding member is always urged by a contact means comprising an elastic force of the thread holding member or a separately provided spring so that the free end of the thread holding member strongly contacts the thread holding receiver, and is loosened at a predetermined time. By means, a force against the urging force may be applied to the yarn holding body to reduce the pressing force of the yarn holding body against the yarn holding receiver.

Next, FIGS. 13 and 14 showing different embodiments of the present invention will be described. These figures show an example in which the loosening means is constituted by a movable blade operating device in the lower thread cutting device. The movable blade operating device not only moves the movable blade 13e within the above-mentioned range, but also cuts the movable blade 13e in FIG. Moveable blade 13e from the position as shown in Fig. 14
Can be moved to the lower thread loosening position away from the thread holder 28e.

In such a configuration, the holding of the lower thread by the thread holder 28e is loosened by moving the movable blade 13e from the position shown in FIG. 13 as shown in FIG.

In addition, functionally considered to be the same or equivalent to those in the previous figure, the same reference numerals as those in the previous figure denote the same parts as in the previous figure.
And duplicated description is omitted.

〔The invention's effect〕

As described above, according to the present invention, when sewing on the cloth N is completed, the lower thread a connected between the cloth N and the shuttle 3 can be cut by reciprocating the movable blade 13,
The cut end a 'of the lower thread a connected to the shuttle 3 after cutting can be held, and as a result, the cloth N can move freely, and the cut end a' of the lower thread is outside the shuttle 3 so that There is an effect that sewing can be started immediately.

Further, when sewing is started again, since the cut end a 'of the lower thread connected to the shuttle 3 is securely held between the movable blade 13 and the thread holder 28, the first rotation of the shuttle 3 causes the blades of the shuttle 3 to rotate. 4
Can prevent the lower thread a from coming off from between the movable blade 13 and the thread holder 28 even if the lower thread a is dislodged. As a result, the lower thread connecting the upper thread b of the first stitch to the shuttle 3 can be prevented. There is an effect that the sewing machine can be securely entangled with a and can be accurately sewn from the beginning.

When the cloth N is moved in accordance with the number of vertical movements of the needle 5 at the start of sewing, the pressing force of the thread holder 28 against the movable blade 13 is reduced by the loosening means 30,
A piece a 'of the lower thread a connected to the first seam c to the cloth
Can be extracted from the space between the movable blade 13 and the thread holder 28 with a weak force. As a result, the cloth N can be freely moved, the sewing pattern can be made accurate, and the cloth N can be prevented from wrinkling. .

[Brief description of the drawings]

BRIEF DESCRIPTION OF THE DRAWINGS The drawings show an embodiment of the present application, FIG. 1 is a perspective view showing a partly broken part, FIG. 2 is a plan view showing a partly omitted part,
FIG. 3 is a longitudinal sectional view, FIG. 4 is a plan view showing the needle plate and the cloth of FIG. 3 omitted, FIG. 5 is a sectional view showing a state immediately before cutting the lower thread, and FIG. FIG. 7 is a cross-sectional view showing a state in which cutting of the thread has been completed, FIG. 7 is a plan view showing the needle plate and cloth of FIG. 6 omitted, FIG. 8 is a cross-sectional view showing a state immediately after sewing is restarted, 9 is a plan view showing the needle plate and the cloth of FIG. 8 omitted,
FIG. 10 is a cross-sectional view showing a state where the first stitch has been completed, FIG. 11 is a cross-sectional view showing a state where the second stitch has been completed, and FIG. 12 is an operation of a balance, a needle, a shuttle, a thread holder, and a cloth movement. FIG. 13 is a partial cross-sectional view for explaining different examples of the loosening means, and FIG. 14 is a partial cross-sectional view showing a state where the holding of the lower thread is loosened by the loosening means. 2 ... needle plate, 3 ... hook, 5 ... needle, N ... cloth, A ... lower thread passage locus, 10 ... fixed blade, 13 ... movable blade, 18 ... thread hooking part, 28 ... ... Thread holding body, 30 ... Thread holding body actuator (loosening means).

Claims (1)

(57) [Claims] 1. A shuttle for lower thread feeding is rotatably provided below the needle plate, a needle for upper thread feeding is provided above and below the needle plate so as to be vertically movable, and the needle is vertically moved. In a sewing machine in which the cloth placed on the needle plate is sewn with the upper thread and the lower thread by rotating the shuttle and rotating the shuttle, the lower thread passage locus between the needle plate and the shuttle below the needle plate The fixed blade is arranged on the side of the fixed blade, and the fixed blade is provided with a movable blade for cutting the bobbin thread in cooperation with the fixed blade. The reciprocating motion beyond the lower thread passage locus is freely configured, and further, the lower thread positioned on the lower thread passage locus is hooked on the movable blade at the time of reversing, and the lower blade is moved with the fixed blade at the cutting position. Between the cloth and the shuttle, a thread hook is provided so as to cut the middle of the lower thread. Near the movable blade to be positioned in location,
A thread holding member having a free end pressed against a movable blade at the cutting position so as to be able to clamp the lower end free end side of the cut lower thread on the shuttle side; Reducing the pressing force on the shuttle-side lower thread sandwiched between the movable blade and the thread holder after at least one or more stitches have been formed in conjunction with the rotation of the shuttle. A sewing machine provided with loosening means to make it easier to pull out.