JPS5971773A - Wiper of sewing machine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The present invention relates to a wiper for a sewing machine.

2. Description of the Related Art Conventionally, a wiper device is known as a device that holds the tip of a needle thread after thread trimming on a copper plate to prevent the needle thread from coming off from the needle at the start of sewing.

However, this wiper device continues to hold the tip of the needle thread even after the sewing machine starts sewing, and the needle thread is pulled out against the holding force of the wiper device. Of the thread, only a small amount of needle thread between the needle and the wiper device is consumed, and most of the needle thread from the needle thread between the needle and the needle thread supply source is consumed.

For this reason, a long needle thread between the button and the wiper device that is not used for seam formation remains at the beginning of the seam, and in order to make the seam beautiful, this needle thread must be cut short with scissors. However, the disadvantage was that the working time was significantly increased.

SUMMARY OF THE INVENTION An object of the present invention is to provide a wiper for a sewing machine that can shorten needle threads that are not used to form seams at the start of sewing without impairing the beauty of the stitches.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

In Figure 1, 1 is a sewing machine, N is a needle supported vertically movably on the machine frame of sewing machine 1, and needle N is below the 10-needle version of the sewing machine.
A known thread cutting means (not shown) is arranged to cut the upper and lower threads connected to the fabric (not shown) when the thread is stopped at the upper position.

2 is a support plate fixed to the lower part of the face plate 3 of the sewing machine L in parallel with the face plate 3 with a certain gap, and 3 is the upper end fixed to the support plate 2, with the free end facing near the tip of the needle N in the upper position. This is a guide rod having a guide groove 34 (see Figs. 2 to 4) on the inside of the bent side.

Reference numeral 4 denotes a needle thread catcher having a hook portion 4α for catching the needle thread T at the lower end and a pin 4h projecting from the upper end, and this needle thread catcher 4 fits into the guide groove a of the guide rod 3. The working position where the hook part 4a crosses the upper thread path between the fabric and the needle hole (the position shown in Figure 2) and the non-working position where the hook part 4a is separated from the upper thread path (the position shown in Figure 3) ) can be moved between.

Reference numeral 5 denotes a needle thread holding piece which is integrally formed at the tip of the guide rod 3 and pinches the needle thread T by coming into contact with the hook portion 4α of the needle thread catcher 4 in the inactive position.

Reference numeral 6 designates an arm whose middle portion is rotatably supported by a step screw 6A on the support plate 2, and whose forked portion 6a formed at the tip is fitted into the bottle 4h.

Reference numeral 7 denotes an electromagnetic solenoid as a moving means for moving the upper thread catcher 4 fixed to the machine frame of the sewing machine, and when it is de-energized, the elastic restoring force of a spring (not shown) causes its drive shaft 7a to move.
is located below, and upon excitation, the drive shaft 7α moves upward against the elastic force of the spring.

Reference numeral 8 denotes a connecting link rotatably supported at the tip of the drive shaft 7a of the electromagnetic solenoid 7 and the base end of the arm body 6, respectively.

FIG. 5 shows the electromagnetic solenoid 70 control means.

In the figure, 9 is a current limiting circuit whose one end is connected to the power supply 10 and the other end is connected to the electromagnetic solenoid 7, and transistors Tri, T
It is equipped with r2. Reference numeral 11 denotes a generator that generates a pulse signal every time the needle N reaches the upper position, counts the pulse signal through a waveform shaping circuit 12 and an AND circuit 13, and calculates the number of pulses set by a digital switch 14AK. It is connected to a stitch number counting means 14 which generates an hourly hand signal and resets in connection with the generation of the thread trimming signal by the operation of the thread trimming means.

In addition, 15. 1 (i is one-shot multi, 17゜1
8 is an OR circuit.

Next, this invention will be explained in detail.

When the sewing machine finishes sewing the cloth and depresses the foot pedal of the sewing machine in the reverse direction, one pulse of the thread trimming signal of level 1-H is generated, and the thread trimming means is activated to cut the upper and lower threads. Further, this thread trimming signal resets the count number of the stitch number counting means 140 to O, and inputs a signal at the rLJ level from the one-shot multi 15 to the OR circuit 17. Further, as for the thread cutting signal, a 1-H'' level signal is directly inputted to the one-shot multi 15 and OR circuit 17, and an rHJ level signal is inputted to the transistor TR2, and the output of the OR circuit 17 is set to rHJ. The transistor TR2 is set to “O” by the rHJ level signal.
"N" state, a large current is output from the transistor TRI to the electromagnetic solenoid 7, and the transistor TR3 also becomes rHJ.
Due to the level signal, the stroke of the drive shaft 7a of the electromagnetic solenoid 7 becomes the maximum, and the second
As shown in the figure, the gold 1 thread catcher moves to a position where it intersects with the needle thread path and captures the needle thread connected to the fabric and needle N.

After that, when the thread trimming signal reaches the rLJ level, the OR circuit 17
The output of transistor TR3 becomes "L" level, and transistor TR3 becomes "O
F Due to the FJ state, the electromagnetic solenoid 7- is de-energized, and the gold 1 thread catcher 4, which has captured the upper thread, is activated by the electromagnetic solenoid 7.
The needle thread is moved to the non-active position by the restoring force of the elastic body, and the needle thread is held between the needle thread holding piece 5 and the sewing work is completed as shown in FIG.

Thereafter, the presser foot is raised, the sewn fabric is taken out, the unstitched cloth is placed in the stitched portion, and the presser foot is lowered to start the sewing machine. When the number of stitches of the sewing machine reaches the number of stitches set in advance by the digital switch 14A, a needle signal of L level is outputted from the total number counting means 14, and a signal of H level is inputted from the one-shot multi 15 to the OR circuit 17.

On the other hand, since no thread trimming signal is output to the one-shot multi 15 or transistor Tγ2, an L level signal is input to turn off the transistor Tr2.

Therefore, an H level signal is output from the OR circuit 17 to turn on the transistor Tra, and the current from the power supply 10 becomes a small current due to the transistor 'l''r2, and the excitation force of the electromagnetic solenoid 7 is weakened. The catcher 4 does not move to the working position where it intersects the upper thread path, and the fourth
As shown in the figure, it moves to the neutral position before the upper thread path and stops. As a result, the tip of the needle thread T is released from the clamping force between the needle thread catcher 4 and the needle thread holding piece 5, and after a few stitches have passed from the start of sewing, the needle thread up to the tip of the needle thread T forms a stitch. As a result, the needle thread remaining at the start of stitching becomes shorter.

Thereafter, the electromagnetic solenoid 7 returns to its original state, forms a stitch of a predetermined length, and then depresses the foot pedal in the opposite direction again to cut the thread and complete the stitching of the cloth.

Note that when an air cylinder is used instead of the electromagnetic solenoid, the same operation can be performed by controlling the air pressure supplied to the air cylinder.

Further, although a configuration has been shown in which the upper thread catcher 4 is controlled by changing the current of one electromagnetic solenoid, it is also possible to control the upper thread catcher 4 by turning on and off the electromagnetic solenoid.

In this case, as shown in FIGS. 6 to 8, two electromagnetic solenoids 7A and 7B are used, and a horizontal rod 19 is supported on their drive shafts 7α and 7h, and the arm body 6 is disposed between the horizontal rods 19. When the thread trimming means is manual, both solenoids 7A and 7B are energized to move the upper thread catcher 4 to an operating position intersecting the upper thread path as shown in FIG. After capturing the thread, the rear solenoids 7A and 7B become de-energized and the needle thread is held between the needle thread holding piece 5. When a needle signal is generated after sewing starts, one of the solenoids 7A and 7B is activated. The control means may be configured to excite only the upper thread 7B and move the upper non-capturing body at the neutral position f to release the upper thread from being clamped.

Further, in this embodiment, the hook portion is moved to the neutral position depending on the number of stitches from the start of sewing, but the hook portion may be moved to the neutral position depending on the starting time from the start of sewing.

As described above, according to the present invention, the number of stitches at the start of sewing and the electromagnetic
A small current is applied to the solenoid to move the needle thread catcher 4 within a range where it does not touch the needle, thereby releasing the upper thread from the needle °N to the tip of the needle thread at the start of sewing. Sufficient thread is used to form the seams, and even if the upper thread is not cut due to leftover threads or stitches at the start of sewing, the stitching can be made sufficiently fuzzy to the extent that it does not spoil the aesthetic appearance of the product. This has the effect of significantly shortening the construction time.

[Brief explanation of drawings]

FIG. 1 is a side view of one embodiment of the present invention, and FIGS.
FIG. 5 is a circuit diagram of the control means of the embodiment shown in FIG. 1, and FIGS. 6 to 8 are operation explanations of other embodiments of the control means. It is a diagram. 4...Needle thread catcher 4α...Hook part 5...Needle thread holding piece 7...Movement means 14...Stitch number counting means-7b lower R

Claims (1)

[Scope of Claims] A needle supported on a sewing machine frame so as to be movable up and down, 1, and thread cutting means for catching one of the needle thread loops and the bobbin thread on the lower surface of the throat plate and cutting the upper and lower threads continuous to the fabric. In a sewing machine equipped with the above-mentioned sewing machine, a hook part is formed at the lower end to catch the needle thread J'+Ii, and the hook part can be moved between an active position where the hook part crosses the upper thread path and an inactive position where the hook part is separated from the upper thread path. an upper thread catcher supported on the machine frame; a needle thread holding piece fixed to the machine frame and in contact with the hook in the inactive position to pinch the copper thread; a moving means for moving the catching body; and a stitch count counter that measures the number of stitches or time, generates a needle signal when a preselected number of stitches or time is reached, and resets or closes in connection with the operation of the thread trimming means. means for moving the hook of the needle thread catcher between an operating position and a non-working position in relation to the operation of the thread trimming means, and moving the hook of the needle thread catcher to hold the needle thread in relation to generation of the needle signal. A wiper for a sewing machine comprising control means for controlling the moving means to move between a neutral position and an inactive position between the piece and the needle path.