JPS6117515B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electric sewing machine, and particularly to a safety device for an industrial sewing machine.

Various types of control devices have been proposed for this type of electric sewing machine, particularly for industrial sewing machines.

1 to 3, a control device for an electric sewing machine using an electromagnetic clutch will be explained.

Figure 1 shows the overall configuration of an industrial sewing machine.The sewing machine main body MA is placed on the table TA.
The sewing machine shaft has a pulley PUL ₂ and a position detection mechanism PS.
is installed.

Pulley PUL ₂ table TA through belt VB
This pulley PUL ₁ is directly connected to _the output shaft of the transmission mechanism TP, which includes a clutch part and a brake part, and the motor
It is now driven by MO.

CB is a controller with a control circuit, and a foot pedal
It is controlled by the output signal of the switch FSW operated by the FP and the position detection mechanism PS.

Furthermore, as shown in FIG. 2, the transmission mechanism TP section includes a clutch plate CLB which is movably disposed in the axial direction between a clutch friction plate CLM and a brake friction plate BRM connected to the rotating shaft of the motor MO, The pulley PUL ₁ is directly connected to this clutch plate CLB.

And the clutch plate CLB above is a clutch coil.
By energizing CL, the clutch friction plate CLM
By engaging with the brake friction plate BRM and rotating, and exciting the brake coil BR, the brake friction plate BRM is engaged and stopped.

Further, as shown in FIG. 3, the clutch coil CL is connected to a power source _V1 via a transistor _T1 , and this transistor _T1 is operated by a clutch signal CLS.

Similarly, the brake coil BR is also connected to the power supply _V1 via a transistor _T2 , and this transistor _T2 is operated by the brake signal BRS.

Furthermore, the TR is a transistor in the thread trimming drive coil.
This _transistor T ₃ is operated by the thread trimming signal TRS.

Furthermore, WP is a thread wiper drive coil, KLT is a presser foot lifter drive coil, and each transistor
It is connected to the power supply V ₁ via T ₄ and T ₅ , and these transistors T ₄ and T ₅ each receive a thread removal signal.
It is controlled by WPS and presser foot lifting signal KLTS.

In the above configuration, when the lower foot pedal P in Fig. 1 is stepped forward, the clutch signal CLS is output by the foot switch FSW, and the clutch coil is activated.
CL is energized via the transistor _T1 , and the clutch plate CLB is pressed against the clutch friction plate CLM, causing the pulley _PUL1 to rotate.

As a result, pulley PUL ₂ is driven via belt VB, and the sewing machine shaft is rotated.

When you release your foot from the foot pedal FP in this state, the foot pedal FP becomes in a neutral state, the position detection mechanism PS detects the lower position of the sewing machine needle, and the detection signal is used to set the clutch signal CLS to zero to set the clutch coil CL. The brake coil BR is deenergized and the brake signal BRS is generated for a short period of time to excite the brake coil BR.

Therefore, the sewing machine shaft is braked, and when the sewing machine needle reaches the lower position, it stops there.

Next, when the foot pedal FP is reversely depressed, the thread trimming signal TRS and the clutch signal CLS are generated simultaneously, the thread trimming drive coil TR and the clutch coil CL are excited, and the sewing machine shaft rotates and the thread trimming operation is also performed at the same time.

When the sewing machine needle reaches the upper position, the position detection mechanism PS generates an upper position signal, and a thread trimming signal is generated.
Turn off TRS and clutch signal CLS at the same time, generate brake signal BRS for a short time to excite brake coil BR, and stop the sewing machine needle at the upper position.

At the same time, the thread removal signal WPS is generated for a short period of time to excite the thread removal drive coil WP to remove the cut thread, and then the presser foot lifting signal KLTS is issued to push up the presser foot and take out the sewing product freely. make it happen.

Each control signal in such conventional equipment is
It is composed of logic elements such as TTL, and even if short-term electrical noise intrudes, it returns to normal after the noise disappears and rarely malfunctions.

However, configuring such conventional devices with logic elements such as TTL requires a large number of elements.
In addition, there are cost and size problems such as a large mounting area, and it has been found that these problems can be greatly improved by using a microcomputer with a higher degree of integration.

However, although this microcomputer is capable of performing functions similar to logic circuits through programming, it is susceptible to malfunctions due to very short-term electrical noise from the outside, and this noise intrusion This causes the program to jump from a normal program routine to another routine, and even after the noise disappears, the original normal operation does not return.
Operational problems may occur.

Furthermore, if large fluctuations in the power supply voltage occur, the microcomputer will no longer operate normally.
The contents of outputs, registers, memory, etc. may go awry.

If the power supply voltage drops sufficiently and you reset the computer and use it, there will be no problem, but if the power supply voltage returns to normal immediately due to a temporary fluctuation, the outputs and registers may be distorted due to the fluctuations in the power supply voltage. Alternatively, since the program is executed based on the contents of memory, there is a risk that the program will not operate normally and cause an unexpected accident.

The present invention has been made in view of the problems of the conventional devices as described above.In a control device that uses a microcomputer in the control circuit, even if an abnormal signal is output from the computer, the sewing machine malfunctions due to the protection circuit. The purpose of this is to protect the operator from danger and prevent damage to the equipment.

The main feature of the present invention is that the control device for an electric sewing machine has at least a part of it a microcomputer, and the output of the control device controls each mechanism according to a predetermined sequence. A protection circuit is added to immediately invalidate the activation signal for the thread removal mechanism when a signal instructing the operation of the thread removal mechanism and the thread removal mechanism is issued at the same time.

An embodiment of the present invention will be described below with reference to FIG. In the figure, DD and UD are the lower position signal and upper position signal of the position detection mechanism PS, respectively.
TSW and LSW are the reverse and forward signals of the foot switch FSW operated by the foot pedal FP.

Also, CLSM, BRSM, TRSM, WPSM and
KLTSM are output signals from the microcomputer MCPU, which are a clutch signal, a brake signal, a thread trimming signal, a thread sweep signal, and a presser foot lifting signal, respectively.

Each of these signals is output in a predetermined sequence by a program stored in the microcomputer MCPU.

Furthermore, HS is a microcomputer MCPU
Another output of the thread trimming signal TRSM is a constant speed holding signal to keep the rotational speed of the sewing machine shaft at a constant low speed while the thread trimming mechanism is operating, and the speed control circuit SCC is connected to the input end of the

Each output terminal of the microcomputer MCPU is connected to each signal terminal for the clutch, brake, thread trimmer, etc. through an AND gate constituting a protection circuit.

In the device of the present invention configured as described above, now,
Clutch signal of microcomputer MCPU
A case will be described in which both CLSM and brake signal BRSM are turned on at the same time, that is, become high level (hereinafter simply referred to as H level).

The clutch signal CLSM is connected to input 1 of the AND gate AND _{1 .}
Input 1 of is at H level, but since the rake signal BRSM is connected to its input 2 via inverter _INV1 , this input 2 is at low level (hereinafter simply referred to as L level).

Therefore, the output of the AND gate _AND1 , that is, the clutch signal CLS, is held at the L level, and the clutch coil CL is not excited, so that the sewing machine is not driven.

Also this clutch signal CLSM, brake signal
Since BRSM is connected to inputs 1 and 2 of AND gate AND ₉ , the output of this AND gate AND ₉ becomes H level.

The output of this AND gate AND ₉ is input to the interrupt signal terminal INT of the microcomputer MCPU via the OR gate OR ₁ , thereby forcing the brake signal BRSM to the H level for a certain period of time and all other output signals to the L level. By programming the clutch signal to
In an abnormal situation where CLSM and brake signal BRSM become H level at the same time, the brake coil BR
only is energized for a certain period of time, and the sewing machine is forcibly stopped.

Therefore, even if the sewing machine is rotating, it will be stopped immediately, and at the same time, the thread trimming, thread sweeping, and presser foot lifting mechanisms will stop all operations, and the alarm ARM will be activated to indicate an abnormal state. It is possible to notify something.

Next, when the thread trimming signal TRSM is turned on, that is, becomes H level, the sewing machine shaft must rotate at a predetermined constant low speed, and the microcomputer MCPU outputs this constant speed holding signal HS. There is.

If this thread trimming signal TRSM and constant speed holding signal HS do not go to H level at the same time, the sewing machine will operate at high speed, which will damage the thread trimming device and lead to unsafe operations such as breaking the sewing machine needle. Become.

Therefore, the thread trimming signal TRSM is AND gate AND ₃
By connecting the constant speed holding signal HS to the input 1 of the AND gate AND ₃ and the input 2 of the AND gate AND 3, the output of the AND gate AND ₃ will be at the L level unless both signals go to the H level. keep
Since the thread trimming signal TRS is not output, the unsafe operation described above does not occur.

Also, this thread trimming signal TRSM is an AND gate.
The constant speed hold signal HS is input to input 1 of AND ₆ .
Since it is connected to input 2 of AND gate AND ₆ via INV ₃ , when both inputs of AND gate AND ₆ become H level, its output becomes an OR gate.
Similarly to the above, the brake is activated for a certain period of time via OR ₁ , and the alarm ARM is activated at the same time.

Next, the thread removal signal WPSM and the presser foot lifting signal
Normal operation for both KLTSM is for the sewing machine needle to stop at the upper position before outputting.

If the sewing machine rotates while removing the thread, the thread remover may come into contact with the sewing machine needle and cause an accident, such as breaking the sewing machine needle, so such operations should never be performed.

Therefore, when the thread removing signal VPSM is at the H level and the thread removing operation is performed, the clutch signal CLSM must be at the L level.

Hence thread-wiping signal WPSM and gate AND ₄
while this AND gate AND ₄
Invert clutch signal CLSM to input 2 of
Yarn removal signal by connecting through INV ₂
When WPSM is at H level and clutch signal CLSM is at H level, the output of AND gate _AND4 is L.
level, and the thread removal signal WPS is not output.

In addition, by connecting the thread removal signal WPSM to the input 1 of the AND gate AND ₇ and the clutch signal CLSM to the input 2, when both inputs of the AND gate AND ₇ become H level, the AND gate
The output of AND ₇ is fed back to the microcomputer MCPU via OR gate OR ₁ to operate the brake for a certain period of time in the same way as described above, stopping the sewing machine and activating the alarm ARM at the same time.

On the other hand, if the presser foot is raised, the sewing machine's built-in feeding device cannot feed the fabric, which not only prevents sewing work but also causes problems such as thread tangles, so when raising the presser foot, The sewing machine must be stopped.

Also, before driving the sewing machine, it is necessary to lower the presser foot to make it ready for sewing.

Therefore, if this presser foot lifting signal KLTSM is connected to input 1 of AND gate AND ₅ , and clutch signal CLSM is connected to its input 2 via inverter INV ₂ , when both signals are at H level, the input of AND gate AND ₅ 1 is at H level and input 2 is at L level, the output of AND gate AND ₅ is at L level, and the presser foot lifting signal KLTS is not output and the presser foot does not operate.

In addition, the clutch signal CLSM and the presser foot lifting signal KLTSM are connected to inputs 1 and 2 of the AND gate _AND8 , so if both signals become H level at the same time, the output of this AND gate _AND8 becomes H level.
Microcomputer through or gate OR ₁
Feedback is sent to the MCPU in the same way as in the previous case, and the brake is operated for a certain period of time and the alarm ARM is activated at the same time.

The above explanation has been about individual abnormal phenomena, but the same applies even if several of these occur at the same time. Since the brake is applied to immediately stop the sewing machine and other operation commands are canceled, the sewing machine can be operated safely even if, for example, an abnormal command signal is output from the microcomputer.

In this way, the present invention prevents malfunctions of the microcomputer due to extremely short-term electrical noise and fluctuations in power supply voltage, and also protects the sewing machine and the operator from erroneous signals generated by malfunctions of the microcomputer itself. It can be protected.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram showing the configuration of an electric sewing machine, Figure 2
1 is a block diagram of the power transmission mechanism shown in FIG. 1, FIG. 3 is a circuit diagram of a drive section in a conventional example, and FIG. 4 is a circuit diagram of a control signal section in an embodiment of the apparatus of the present invention. MA...sewing machine body, MO...motor, CL...
Clutch coil, BR...brake coil,
MCPU...Microcomputer.

Claims (1)

[Scope of Claims] 1. A clutch mechanism for transmitting the rotational force of the motor to the sewing machine and driving it, a brake mechanism for applying braking force to the sewing machine, and stopping the needle of the sewing machine at a predetermined position. a thread trimming mechanism that automatically cuts the sewing thread after sewing is finished; a thread removal mechanism that removes threads cut by the thread trimming mechanism; and controls for controlling the operations of each of the mechanisms described above. In an electric sewing machine equipped with a device, the control device includes at least a part of a microcomputer, and when a command signal is simultaneously outputted from the microcomputer to operate a clutch mechanism and a thread removal mechanism, the control device performs a thread removal operation. Safety of an electric sewing machine, characterized in that it is equipped with a protection circuit that immediately disables the operation signal of the mechanism to stop the operation of the thread removing mechanism, simultaneously cancels the operation signal of the clutch mechanism, and operates the brake mechanism for a required short time. Device. 2. In claim 1, the protection circuit is characterized in that it is equipped with an alarm device that indicates that command signals for operating the clutch mechanism and the thread removal mechanism are generated at the same time. Safety device for electric sewing machines.