JPS5933399B2 - Needle fixed position stop device for automatic thread trimming sewing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a needle fixed position stopping device for an automatic thread trimming sewing machine.

Conventionally, the needle is stopped at a lower position by releasing the toe side of the foot pedal (sewing machine drive) connected to a motor with a clutch for driving the sewing machine, and the needle is raised from the lower position by operating the knee pedal. Stop it in the upper position,
Further, a needle fixed position stopping device for an automatic thread trimming sewing machine is configured to stop the needle in an upper position and cut the thread in the upward process by simultaneously operating the knee pedal and pressing the heel side of the foot pedal. is provided.

However, in this device, both pedals must be used depending on the work mode, so the operation is cumbersome and easy to make mistakes.

Moreover, the operation of the knee pedal moves the worker's knee laterally, whereas the heel operation of the foot pedal moves the worker's heel downward.
Since the directions of movement of the two pedals are different, performing both operations at the same time causes physical fatigue to the worker, which, together with the aforementioned troublesome use of the two pedals, causes a decrease in work efficiency.

Therefore, the present invention eliminates such defects, and one embodiment will be described below.

In the figure, 1 is a sewing machine having a thread cutting device (not shown), and has a main shaft 2 and a needle 3 that reciprocates up and down in conjunction with the main shaft 2.

4 is a drive means for driving the sewing machine 3, and a flywheel 7 is fixed to a rotor shaft 6 of the main motor 5.

8 has a clutch disc 9 on the side facing the flywheel 7.
is a fixed output shaft, which is rotatably and axially slidably attached to the bracket of the main motor 5, and is connected to the main shaft 2 of the sewing machine 1 through an end 10 opposite to the flywheel 7. connected.

Reference numeral 11 denotes a brake shaft rotatably supported around the output shaft 80, one side of which faces the clutch disc 9, and a worm wheel 12 formed on the other side.

Reference numeral 13 denotes a through worm that meshes with the worm wheel 12, the shaft portion 14 of which extends on both sides, and a rotary disk 15 at its end.
is fixed, and the other end is formed as a spline shaft,
A movable platen 16 is fitted.

A brake coil 17 is attached to the bracket of the main motor 5, and when it is energized, it attracts the movable platen 16 toward the fixed brake 18 and stops the rotation of the shaft portion 14.

Reference numeral 19 denotes an auxiliary motor, the end of whose rotor shaft 20 is formed as a spline shaft, and a movable plate 21 facing the rotary plate 15 is fitted therein.

22 is a drive coil, and when it is energized, the movable platen 2
1 toward the rotary disk 15, and the rotation of the auxiliary motor 19 is transmitted to the shaft portion 14.

Reference numeral 23 denotes a clutch lever, which includes a main lever 25 whose intermediate portion is rotatably supported by the shaft portion 24 on the bracket of the main motor 5 and whose upper end is operatively connected to the output shaft 8; It consists of an auxiliary lever 27 whose intermediate portion is rotatably supported by a shaft portion 26 at the lower end thereof.

28 is a foot pedal connected to the auxiliary lever 27 of the clutch lever 25 via a connecting rod 29;
The operation of the sewing machine 1 can be controlled by depressing the .

Further, the foot pedal 28 is provided in the clutch lever 23.
A normally open front depression switch 31 is provided which is closed by an auxiliary lever 27 that is rotated at the beginning of the toe-side depression.

Furthermore, even after the front depression switch 31 is closed, if the foot pedal 28 is depressed toward the toe side, the clutch lever 23
The entire body is rotated and the clutch disc 9 is moved toward the flywheel γ.

Also, when the depression is released, the clutch lever 23
is moved by the action of the return spring 32, and the clutch disc 9
comes to be engaged with the brake shaft 11.

Reference numeral 33 denotes a manual operation lever whose base end is rotatably supported 34 on a mounting frame fixed to the back of the sewing machine 1, and whose free end extends to the front of the jaw of the sewing machine 1 and is operated by the operator's hand. It is formed as an operation section 35.

The manual operating lever 33 is given a rotational force in the counterclockwise direction in FIG. 2 by a spring (not shown), and the rotational force is applied when the base of the manual lever 330 engages with a stopper 36 provided on the mounting frame. The manual operation lever 33 is always kept at the position shown in FIG.

Reference numeral 37 denotes a normally open needle lift switch fixed to the mounting frame, which is closed when the manual operation lever 33 is pressed and rotated against the action of a spring.

The external input means is constituted by the members indicated by the numbers 33 to 37 above.

Instead of configuring this external input means as described above, the needle raising switch 37 may simply be placed and attached to the front surface of the jaw of the sewing machine 1.

In addition, this external input means is not limited to the front surface of the jaw of the sewing machine 1, but is also available near the needle post reciprocating path of the sewing machine 1 (for example, below the jaw, on the side of the face plate of the arm, on the bed surface near the needle plate, etc.) You can place it anywhere.

38 is a rotary plate fixed to the end of the main shaft 2, and one permanent magnet piece 39 is fixed thereto.

Reference numeral 40 denotes a normally open first reed switch which is disposed in correspondence with the position of the permanent magnet piece 39 below the needle, and is closed by the permanent magnet piece 39 when the needle reaches the downward position.

Reference numeral 41 denotes a normally open second reed switch disposed corresponding to the above-mentioned position of the permanent magnet piece 39 above the needle, and is closed by the permanent magnet piece 39 when the needle 3 reaches the above position.

Reference numeral 42 denotes a normally open third reed switch disposed corresponding to the thread cutting position of the permanent magnet piece 39, which is disposed between the first and second reed switches 40 and 41, and is used to operate the thread cutting device. When the position is reached, it is closed by its permanent magnet piece 39.

The permanent magnet piece 39 and the first and second pieces. The three reed switches 40, 41, and 42 constitute a position detecting means.

Next, the electrical configuration will be explained with reference to FIG.

The configuration of this electric circuit is a configuration of a negative logic circuit in which a negative potential is a logical value of "1".

43 is the negative power line, 44 is the positive power line, 45
48 is a NOR circuit for inverting the signal of the first reed switch 40; 44 is the NOR circuit 48;
and a signal from the front depression switch 31 as input, and its output is applied to the NOR circuit 46 as a reset input for the flip-flop 45 via a delay timer 50 set to a delay time of, for example, 50 m5ec.

A dynamic flip-flop 51 receives the outputs from the NOR circuit 49 and the delay timer 50, and generates an output signal of "1" when the input signal from the NOR circuit 49 rises. Generates an output signal of "0" at the rising edge of the input signal.

Reference numeral 51 denotes a NOR circuit which receives the outputs of the needle rise switch 37 and the next stage NOR circuit 52, 53 a NOR circuit which inverts the output from the third reed switch 42, and 54 a NOR circuit which receives the output from the needle rise switch 37. A NOR circuit 55 inverts the output; 55 is a NOR circuit that receives the outputs of the NOR circuit 54 and the NOR circuit 53; and 56 is a NOR circuit that inverts the output of the NOR circuit 55.

57 is a NOR circuit whose inputs are the output from the second reed switch 41 and the output from the NOR circuit 58 at the next stage.

Further, the NOR circuit 46 inputs the output of a reset circuit 59 that provides a pulse as a reset input signal only when the power is turned on, and the outputs of the delay timer 50 and the NOR circuit 47. And the output of the front depression switch 31 is used as input.

Further, the NOR circuit 52 receives the output of the flip-flop 45 and the outputs of the NOR circuit 51 and the reset circuit 59, and the NOR circuit 58 receives the output of the flip-flop 45, the reset circuit 59, and the NOR circuit 57. , each output of the NOR circuit 70 is input.

Reference numeral 60 denotes an OR power amplifier circuit with a negative terminal for controlling energization/disconnection of the drive coil 22, and its positive input terminals tl,
At t2, the flip-flop 45 and the NOR circuit 5
2 are added as inputs, and the negative input terminal t
3, the output of the NOR circuit 58 is added as an input,
Furthermore, the positive output terminal t4 is connected to the power supply line 39 via the drive coil 22.

Reference numeral 61 denotes an OR power amplifier circuit for turning off the power to the brake coil 17, and inputs are given from the negative output terminal t5 of the OR power amplifier circuit 60 and the NOR circuit 58, respectively.

Reference numeral 62 denotes a Noah power amplifier circuit for cutting off the power to the thread cutting coil 63 for placing the thread cutting device in an operating state; The output is the input.

Similarly, the thread cutting coil 63 serves to connect a clutch means provided between the thread cutting blades arranged around the hook and the hook shaft, and is once energized and then energized again. The thread cutting blade is driven by the hook shaft until thread cutting is completed, and is automatically stopped at the starting position after thread cutting is completed.

The thread cutting device is not limited to this type, and various other devices can be used.

In the above configuration, the output of the NOR circuit is "0" when at least one input signal is "11", and the output is "1" only when all inputs are "0".

In an OR power amplifier circuit with a negative terminal, the negative input terminal t3
Only when one of the other positive input terminals is "0" and one of the other positive input terminals is "1", the positive output terminal becomes "1" and the negative output terminal becomes "10".

Next, the operation of the needle fixed position stopping device constructed as described above will be explained step by step.

(1) Turning on the power When the power is turned on, the main motor 5 and the auxiliary motor 19 are driven, and at this time the flywheel 7 and the movable platen 21 rotate idly.

At this time, the reset circuit 59 also outputs the flip-flop 4.
5's NOR circuit 46, NOR circuit 42, and NOR circuit 58 have "
A signal of ``1'' is added, and both outputs become ``O''.

Even after the reset signal of the reset circuit 59 is erased, all of these elements continue to maintain their states.

That is, a signal of "0" is applied to one input terminal of the NOR circuit 70 from the output terminal of the NOR circuit 52, the manual operation lever 33 is inactive, and the needle raising switch 37 is closed to the other input terminal. Since this is not the case, a signal of "0" is added, and an input of "1" is added to the NOR circuit 52.

In addition, the NOR circuit 58 has the same number as "1" in the NOR circuit 70.
Since the signal is added as input, the output is ``
0".

Furthermore, the output of "0" from the NOR circuit 46 is applied as an input to the NOR circuit 47 of the flip-flop 45, and at the same time, since the front depression switch 31 is not closed, the input therefrom is rOJ, and the NOR circuit 46 An output of ``1'' is added to the input.

Therefore, the flip-flop 45 is stable in this state.

Therefore, all the input signals of the OR power amplifier circuit 60 are
0", and the output of the positive output terminal t4 becomes "0", and the drive coil 22 is energized.

Further, an output of "1" is applied from the negative output terminal t5 to the OR power amplifier circuit 61, and the brake coil 17
is encouraged.

Due to the energization of the brake coil 17, the movable platen 16 is attracted by the fixed brake 18, and the rotation of the brake shaft 11 is stopped via the shaft portion 1'4, that is, the worm 13, and the worm wheel 12.

Further, since the clutch disc 9 is also pressed against the brake shaft 11 by the return spring 33, the output shaft 8 and the belt 10
The main shaft 2 of the sewing machine 1 is also stopped from rotating.

Q) Sewing operation When the foot pedal 28 is depressed toward the toe side, the auxiliary lever 27 is first rotated and the front depression switch 31 is closed.

As a result, the NOR circuit 47 of the flip-flop 45 has "
1'' is applied to reverse the stable state of the flip-flop 45.

The inverted “1” output is the OR power amplifier circuit 6
0 is applied to the positive input terminal t1.

Further, the "1" output of the flip-flop 45 is also applied to the NOR circuits 52 and 58, but its output state remains unchanged.

As a result, an output of "1" appears from the positive output terminal t4 of the OR power amplifier circuit 60, and the drive coil 22 is energized, and at the same time, an output of "0" appears from the negative output terminal t5, and the OR power amplifier circuit 61 The brake coil 17 is energized via.

Thereby, the movable platen 21 is pressed against the rotary plate 15, and the rotation of the auxiliary motor 19 is transmitted to the brake shaft 11 via the shaft portion 14, the worm 13, and the worm wheel 12.
The 110 rotations of the brake shaft are transmitted to the sewing machine 1 via the clutch disc 9, and the sewing machine 1 is operated at a low speed.

Furthermore, when the foot pedal 28 is depressed deeply toward the toe side, the clutch lever 23 is rotated around the shaft portion 24, and the clutch disc 9 is also separated from the brake shaft 11 and the flywheel 7
becomes engaged with.

As a result, the sewing machine 1 is rotated by the main motor 5 at high speed.

During this time, the brake shaft 11 continues to rotate idly.

(3) Release of the toe side of the foot pedal (needle down stop) When the toe side of the foot pedal 28 is released and returned to the neutral position after the required sewing is completed, the clutch disc 9 is activated by the action of the return spring 33. As a result, the brake shaft 11 is pressed against the brake shaft 11.

At this time, due to inertia, the clutch disc 9, which is rotating at high speed, contacts the brake shaft 11, which is rotating at low speed, and the clutch disc 9, that is, the sewing machine 1, is rapidly decelerated until it is driven by the brake shaft 11. .

At the same time as the toe side of the foot pedal 28 is released, a signal "0" is applied to one input terminal of the NOR circuit 49, and the signal "0" is applied to the other input terminal every time the first reed switch 40 is closed. An output of "0" inverted by the NOR circuit 48 is added as an input to the delay timer 50, and as a result, an input of "1" is added to the delay timer 50.

However, while the sewing machine 1 is in the process of decelerating, the closing time interval of the first reed switch 40 is short, so that the delay timer 50 does not output any output.

However, until the clutch disc 9 was driven at low speed by the auxiliary motor 19 via the brake shaft 11, the sewing machine 1
When the rotation of ``l'' is decelerated, the delay timer 50
” is generated, which is sent to the flip-flop 45.
, and resets the flip-flop 45 in the same manner as in the power-on state.

As a result, the OR power amplifier circuit 59 energizes the drive coil 22 and energizes the brake coil 17 in the same way as when the power is turned on.

Therefore, the needle 3 of the sewing machine 1 is immediately stopped at that position, that is, the position below the needle.

Incidentally, when the output signal from the delay timer 50 rises, the dynamic flip-flop 51 generates an output of "0".

(4) Needle up stop without thread trimming To stop the needle in the upper position from the current state in which the needle is stopped in the lower position, the operator instantly operates the operating part 35 of the manual operation lever 33 by hand. and be released immediately.

As a result, the inclined rise switch 37 is temporarily closed.
The resulting signal "1" is applied as an input to the NOR circuit 70, and from the NOR circuit 70, a signal "0" is applied as an input to the NOR circuit 52.

Since a signal of "0" is applied to the NOR circuit 52 from the flip-flop 45 and the reset circuit 59, "
1” is generated.

At this time, the NOR circuit 57 receives a signal "10" from the next stage NOR circuit 58 to one input terminal, and the other input terminal has the second reed switch 41 open, so the signal "-" is applied to one input terminal of the NOR circuit 57. An input of “〇” is added, and its output is “1”.

Since this output of "1" is applied to the NOR circuit 58, the output of the NOR circuit 58 is "0".

As a result, the positive input terminal tL of the OR power amplifier circuit 60
rOJ to t2 and negative input terminal t3.

Signals I'''IJ, rOJ are added as inputs, and riJ, rO are output to the positive output terminal t4 and negative output terminal t5.
Generates an output J.

As a result, the drive coil 22 is energized again and at the same time the brake coil 11 is energized, the sewing machine 1 is driven at a low speed and the needle 3 is raised.

When the needle 3 reaches the upper position, the second reed switch 4
1 is closed, and an input of "1" is applied to the NOR circuit 57.

In addition, the NOR circuit 58 receives 10 from the NOR circuit 57.
An output of ``,'' an output of ``0'' from the flip-flop 45, an output of ``0'' from the reset circuit 59, and an output of ``0'' from the NOR circuit 70 are added as inputs, respectively. occurs.

As a result, the positive input terminal tl of the OR power amplifier circuit 60
, t2 and negative input terminal t3 have rOJ, rlJ, r
An input lJ is applied, and outputs rOJ and rlJ are displayed from the positive output terminal t4 and negative output terminal t5.

As a result, the drive coil 22 is energized, the brake coil 17 is energized, and the sewing machine 1 is immediately stopped at the position where the needle 3 reaches the upper position.

(5) Needle up stop accompanied by thread trimming In this case as well, it is sufficient to operate the manual operation lever 33 five times as described above, but it is necessary to continue this operation.

By operating the manual operation lever, the needle 3 starts to move upward from the lower position in exactly the same way as in the case without thread trimming.

Therefore, the lead 3 switch 42 for thread trimming is closed, and the resulting signal "1" is sent to the NOR circuit 5.
3, and a signal of "0" is applied to one input terminal of the NOR circuit 55, but at this time, the needle up valve switch is also applied to the other input terminal by operating the manual operation lever 33.
Since the signal "1" generated by the closing of 43T is inverted and added to the signal "0" by the NOR circuit 54, its output is "1".

The "1" signal is inverted to a "0" signal by the NOR circuit 56 and is applied to one input terminal of the NOR power amplifier circuit 62.

Further, the Noah power amplifier circuit 62 includes a Noah circuit 70.
``0'' output from flip-flop 45, 1 from flip-flop 45
An output of "0" and an output of "0" from the dynamic flip-flop 45 are respectively applied as inputs, and an output signal of "1" is generated from the NOR power amplifier 61 to energize the thread cutting coil 63.

The thread cutting coil 63 is energized by the third reed switch 4.
2 is closed, and its reed switch 4
It is castrated by opening 2.

The clutch means between the thread cutting blade and the hook shaft is connected by the energization of the thread cutting coil 63, and the thread cutting blade is rotated by the hook shaft regardless of the subsequent energization of the coil, and the needle is in the upper position. Cut the thread before reaching .

After the thread trimming is completed, when the needle 3 reaches the upper position and the second reed switch 41 is closed, the needle is stopped in the same manner as described above.

The difference between a needle up stop without thread trimming and a needle up stop with thread trimming is determined by the operating time of the manual operation lever 33, that is, the length of the closing time of the needle up valve switch 37.

If the needle up valve switch 37 is opened after the needle begins to rise from the lower position but before the reed switch 42 for thread trimming is closed, one input terminal of the NOR circuit 55 is supplied via the NOR circuit 54. Since the input of "1" is applied, the output of "0" is generated from the NOR circuit 55 regardless of the operating state of the reed switch 42 for thread trimming, and this is inverted by the NOR circuit 56 to generate the output of the NOR power amplifier. circuit 6
2 as an input of "1", the thread cutting coil 63 is not operated.

In other words, thread trimming and needle up stop are performed only when the needle up valve switch 37 is kept closed until at least the third reed switch 42 for thread trimming is closed.

In fact, in the case of stopping the needle up without thread trimming, it is only necessary to operate the manual operation lever 33 for a moment.

The reason why the dynamic flip-flop 51 is provided in this embodiment is as follows.

In this circuit, the flip-flop 45 outputs the rO
An output J is applied to the Noah power amplifier circuit 62 for operating the thread trimming coil 63, and the thread trimming device is operated.

However, if the foot pedal 28 is depressed toward the toe side after the needle 3 is stopped in the downward position and the front pedal switch 31 is malfunctioning, and the sewing machine is driven at high speed, the flip-flop 45 is not reversed. The output remains at "0", and if the manual operation lever 33 is suddenly operated by mistake and the third reed switch 42 for thread trimming is closed, the clutch disc 9 will close the flywheel 7. The thread trimming coil 63 is energized while it is inertially rotating at high speed away from the sewing machine, and as a result, the thread trimming device is operated at high speed of the sewing machine.

Therefore, when the thread cutting device reaches the thread cutting end position, its thread cutting blade is not stopped at the correct position, resulting in damage to the thread cutting device.

However, by providing the dynamic flip-flop 51, even if the front depression switch 31 is out of order (that is, the input from the front depression switch 31 is 10%).
) When the sewing machine is started by pressing the toe side of the foot pedal, the first reed switch 40 for detecting the lower position of the needle is closed, and the dynamic flip-flop 51 is output at the rising edge of the signal "1" from the NOR circuit 49. The output signal becomes "1", and the signal "1" is added as an input to the Noah power amplifier circuit 62, so even if the manual operation lever 33 is accidentally operated suddenly, the thread trimming coil 63
The thread cutting device is not energized and the thread cutting device is not damaged.

In the above embodiment, the needle fixed position stopping device manually operated by the operator is embodied in a sewing machine in which the needle is stopped downward by releasing the foot pedal. It can also be used in various types of sewing machines, such as sewing machines in which the needle does not stop at a fixed position, but instead stops at a downward position by the foot of the heel of the pedal.

Furthermore, in the above embodiment, the main motor 5 and the auxiliary motor 1
9 is used, however, a single variable speed motor may be used, or an electromagnetic clutch or an electromagnetic brake may be used to obtain high and low speeds from a single motor.

As described in detail above, the present invention is capable of raising the needle from a lower position and stopping it at an upper position by operating an external input means provided near the needle reciprocating path of the sewing machine and operated by the operator's hand. At the same time, the thread trimming device is activated only when the operation is continued until the thread trimming position is detected by the position detection means, so that the needle up stop without thread trimming and the needle up stop with thread trimming are possible. The operator can easily use the different operations depending on the time interval between manual operations, and the operation is simple and does not cause mental or physical fatigue to the operator (and work efficiency is improved).

In particular, since the external input means is provided near the needle reciprocating path of the sewing machine, excellent effects such as further ease of handling are achieved.

[Brief explanation of the drawing]

FIG. 1 is an overall view of the mechanical structure, FIG. 2 is a left side view of the sewing machine showing a portion of the manual operation lever, and FIG. 3 is a logic circuit diagram. In the figure, 1 is a sewing machine, 3 is a needle, 401 is a drive means, 17 is a brake coil, 22 is a drive coil, 28 is a foot pedal,
31 is a front depression switch, 33 is a manual operation lever, 37
40 is the needle upper and outer switch, 40 is the first reed switch, 41
is a second reed switch, 42 is a third reed switch, 45 is a flip-flop, 46 to 49. 52 to 5
5. 56 to 58 and 70 are NOR circuits, 50 is a delay timer, 59 is a reset circuit, 60, 61 is an OR power amplifier circuit, 62 is a NOR power amplifier circuit, and 63 is a thread trimming coil.

Claims (1)

[Claims] 1. A sewing machine having a thread cutting device, a driving means for driving the sewing machine, a brake means for the sewing machine, and a means for detecting the vertical position of the needle of the sewing machine and the thread cutting position between the vertical positions. An automatic thread trimming sewing machine comprising a position detecting means and a foot pedal operatively connected to the first driving means for controlling the operation of the sewing machine,
After the sewing machine is operated at high speed by the foot pedal, the sewing machine is brought into a low speed operation state via the drive means in response to a release operation of the pedal or an operation after the pedal is released, and the output signal is detected by the position detection means generated in that state. a first control means for operating the brake means according to a needle lowering signal;
an external input means provided near the needle post double-acting passage of the sewing machine and operated by the hand of the operator; a second control means for raising the needle from the needle-down state and operating the brake means again when the needle-up position is detected by the position detection means; and the needle is raised by the second control means. and a third control means for bringing the thread trimming device into an operating state only when the operation of the external input means continues until the thread cutting position is detected by the position detection means during the period. Needle fixed position stop device.