JPS5946632B2 - Electric sewing machine safety protection system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention generally relates to a safety protection system for electric sewing machines, including industrial sewing machines.

First, the conventional technology of this type of electric sewing machine is shown in Figures 1 and 2.
This will be explained next using figures.

That is, in an electric sewing machine, as shown in FIG.
It is simply called CLM.

) and clutch plate CL B (hereinafter simply referred to as CLB).

), and there are methods that transmit power directly to the sewing machine from a DC motor, but they are basically the same in terms of controlling the sewing machine.

Therefore, an example using an electromagnetic clutch will be explained here.

In Fig. 1, when driving the sewing machine SM, by passing current through the clutch coil CL, the CLB is moved by electromagnetic force.
is pressed against CLM to transfer the power of motor MOTOR to pulley P.
It is transmitted to the sewing machine SM via L2, belt vv, and pulley PL1.

When stopping the sewing machine SM, a current is applied to the brake coil BR to press the CLB against the brake friction plate BFLM to stop the sewing machine SM.

By the way, with the recent development of this type of sewing machine, complicated control has come to be performed.

As an example, one with automatic thread trimming and vertical needle stop control will be explained with reference to FIG.

In an electric sewing machine, especially an industrial sewing machine, commands to the sewing machine are given by a foot pedal FP as shown in the figure.

When this foot pedal FP is stepped forward, the command front pedal switch LSW is turned on and becomes H level, and when it is stepped in the opposite direction, the command road switch TSW is turned on and becomes H level. In the neutral case where the foot pedal FP is not pressed, both the switches LSW and TSW are off and at the L level.

In addition, there is an upper position detector UD and a lower position detector DD that detect the upper and lower positions of the sewing machine needle, and output L level signals at the upper and lower positions, respectively.

Furthermore, there is a finger speed generator T-G that detects the speed of the sewing machine, and a speed control circuit SPC obtains the sewing machine speed from this T-G and keeps the speed constant.

The output of this speed control circuit SPC is the clutch coil CL
and a signal that drives the brake coil BR. Both signals are a speed control enable signal 5-DRIVE (hereinafter referred to as the 5-DRIV'E signal) generated by the sequence control section.

) is enabled.゛Therefore, 5-DRIV
Speed control is enabled only when the E signal is on, and the sewing machine is operated at a constant speed.

The operation of the above sequence part will be explained next.

First, step forward on the foot pedal FP and press the command forward switch LS.
When W is turned on and set to H level, the output of OR circuit OR2 becomes H level and outputs the 5-DRIVE signal, and the AND
Circuit AND3. Since the single-person power of AND4 is set to H level, the clutch coil C is adjusted according to the output of the speed control circuit SPC.
L and brake coil BR are excited and the sewing machine continues to operate at a constant speed.

Next, when the foot pedal FP is set to neutral, the command front switch LSW becomes level L, the input to the OR circuit OR2 is cut off, and the 5-DRIVE signal disappears.

In this case, when the lower position signal of the lower position detector DD is at H level, the AND circuit AND2 goes to H level and the OR
An input is given to the input 3 of the circuit OR2, and the 5-DRIVE signal is output to rotate the sewing machine, but when the lower position is reached, the signal from the lower position detector DD becomes L level as described above, and the AND circuit The output of AND2 and OR circuit OR2 is set to L.
This eliminates the 5-DRIVE signal as a level.

At the same time, the output of the NOR circuit N0R2 goes to H level, sends a signal to the mono multi MM, sets the Q output to H level for a certain period of time, excites the brake coil BR to apply the brakes, and lowers the sewing machine to the lower position. It is something that makes it stop.

Furthermore, move the foot pedal FP to the road and command road switch TS.
When W is set to H level, flip-flop FF1. FF
2 are both set and the Q output becomes H level, so
The automatic thread trimming coil TRIM is energized and the automatic thread trimming mechanism operates.

At the same time, the signal from the upper position detector UD is at H level, the output of AND circuit AND1 is at H level, and OR
Since input 1 of circuit OR2 becomes H level, 5-DRIV
The E signal is output and the sewing machine rotates.

When the upper position is detected, the signal from the upper position detector UD becomes L level, so the flip-flop FF2 is reset, the automatic thread trimming mechanism is turned off, and the 5-DR
The IVE signal disappears and the sewing machine stops driving.

At the same time, NOR circuit N0R1 and OR circuit OR1
operates, mono multi MM is turned on, and for a certain period of time,
The brake coil BR and the wiper thread removal coil WP are turned on to remove the thread and stop the sewing machine at the upper position.

As described above, one thread is dynamically stopped at the upper and lower positions, and the thread is automatically cut.

However, in the above-mentioned sewing machine, the needle is handled and operated by an unspecified number of people, so sufficient measures must be taken to ensure its safety.

Regarding these points, in the sewing machine mentioned above, the mounting position of the command front switch LSW and the road switch TSW that give commands needs to be wired with lead wires to other circuits due to the relationship with the foot pedal FP. - Considering the case where the power wire is disconnected, both switches LSW and TSW mentioned above will be turned on at the same time, and the sewing machine will be driven during thread wiping, and the brake coil BR and clutch coil CL will operate at the same time. This was extremely dangerous as it could cause the needle to fly off and the motor to burn out.

In addition, even if there is noise, the command front switch LSW
Similarly to the above, it was also dangerous if it was mistakenly determined that the command road switch TSW was turned on at the same time.

The present invention prevents and eliminates the various dangers associated with the conventional sewing machine.In short, the sewing machine malfunctions due to the front foot of the command given by the foot pedal, failure of the road switch, disconnection of wiring, etc. The object of the present invention is to provide a protection method for an electric sewing machine that prevents the sewing machine from becoming dangerous and provides a means for safely controlling the sewing machine.

The safety protection system for the electric sewing machine according to the present invention includes a mechanism that drives the sewing machine using a motor, a mechanism that stops the sewing machine using a brake, an automatic thread trimming mechanism that automatically trims threads, and a foot switch that issues commands to the sewing machine. and in which each of these mechanisms is controlled by electric signals, the front pedal signal that gives a drive command to the sewing machine by the front pedal of the foot switch and the road signal that gives a thread trimming command due to the road are turned on at the same time. When a situation that should never occur is detected,
The operation of the sewing machine drive mechanism and automatic thread trimming mechanism is immediately disabled.

Additionally, in the present invention, the command front switch and the command road switch, which are the command switches of the sewing machine, are not turned on at the same time under normal conditions, so the front and road switches are always checked and the command front switch and road switch are turned on at the same time. If the switch is turned on, it is determined that this is a situation that should never occur, and the sewing machine is immediately stopped to prevent danger due to malfunction.

An embodiment of the present invention will now be described with reference to FIG. 3, with reference also to FIG.

Note that in FIG. 3, parts with the same symbols as in FIG. 2 indicate equivalent parts.

Here, to explain in detail what is shown in Figure 1 again, SM is a sewing machine, in short, the sewing machine itself,
Belt v from pulley PL2 directly connected to clutch plate CLB
The sewing machine SM is directly connected to a position detection device PD that detects the vertical position of the sewing machine needle NID and a finger speed generator T-G that detects the sewing machine speed. be.

In addition, brake friction plates B are provided on both sides of the clutch plate CLB.
Clutch friction plate CL directly connected to RM and motor MOTOR
M is arranged, and by applying current to the clutch coil CL, the clutch plate CL B is connected to the clutch friction plate qLM.
The power of the motor MOTOR is transmitted to the sewing machine SM to drive it.

Furthermore, by energizing the brake coil BR, the clutch plate CLB is pressed against the brake friction plate BRM, and the sewing machine S
Stop M.

Note that in the figure, TAB is a table.

What is shown in FIG. 3 is a control circuit section according to one embodiment.

UD and DD are the upper position detector and lower position detector of the sewing machine needle NID, respectively, which output a level L output when the upper position or lower position is reached.

In addition, LSW and TSW are both command front pedal and road switches that are linked to the foot pedal, as shown in Fig. 2. When the foot pedal is pressed forward, the switch LSW turns on and outputs an H level output. When the vehicle is on the road, the switch TSW is turned on and outputs an H level output. Furthermore, in a neutral state where the foot pedal is not pressed, both switches are turned off and output is at the L level.

TG is a finger speed generator connected to the input of the speed control circuit SPC that keeps the speed constant.

There are two outputs of this speed control circuit SPC, which are:
These are the signal C for the clutch coil CL and the signal port for the brake coil BR.

The output of the above signal C is connected to the input 2 of the AND circuit AND4, and the output of the signal port is connected to the AND circuit AND4.
Connected to input 2 of 3.

The output of the upper position detector UD is connected to the reset terminal R of the flip-flop FF2 through NV1 of the INV circuit and to the AN
It is connected to input 1 of D circuit AND1.

The output of the lower position detector DD is an AND circuit AND.

Connect to input 1 of

The command front switch LSW connects the reset terminal R of the flip-flop FF1, the input 2 of the NOR circuit N0R2, and the NOR circuit N0R2.
AND circuit AN through input 2 of AND circuit NAND, input 2 of OR circuit OR2, and 1Nv circuit NV2.
These are connected to input 2 of D2.

The command road switch TSW is a flip-flop FF7.
Set terminal S of FF2 and NAND AND circuit AND1
It is connected to 1.

The output Q of flip-flop FF2 is output from the AND circuit AND
7's input 1, and this AND7's input 2 is the AND circuit A.
ND6. The input 2 of AND8 and the input of INV circuit ■N■3 are connected to the output of NAND circuit NAND1, and the output of ■Nv3 above is connected to input 2 of OR circuit OR4.
It is connected with.

The output of the AND circuit AND7 is connected to the base of the transistor T1 through the resistor R5, and the collector of the transistor T1 is connected to the power supply V through the automatic thread trimming coil TRIM.

The output Q of the flip-flop FF is an AND circuit AND
, the output Q is the input 2 of the NOR circuit N0R1.
I am connected to.

The output of the AND circuit AND1 is connected to the input 1 of the NOR circuit N0R7, and the output of this N0R1 is connected to the input 1 of the OR circuit OR0 and the input 1 of the AND circuit AND8.

The output of the OR circuit OR2 is the input 1 of the AND circuit AND6.
Then, the output of this AND6 is connected to AND circuits AND3 and AN
It is connected to input 1 of D.

The output of the NOR circuit N0R2 is the input 2 of the OR circuit OR1.
The output of this OR is input 1 of the OR circuit OR4,
Each is connected.

The output of the OR circuit OR4 is connected to the input B of the monomulti MM, and the output Q of the monomulti MM is connected to the AND circuit AND,
The input 2 of the OR circuit OR3 is connected to the input 2 of the OR circuit OR3, and the input 2 of the OR3 is connected to the output of the AND circuit AND3.

Input 1 of the AND circuit AND5 is connected to the output of the AND circuit AND8, and the output of this AND5 is connected to the resistor R8.
The output of the OR circuit OR3 is connected to the base of the transistor T2 through the resistor R6, and the output of the AND circuit AND4 is connected to the base of the transistor T4 through the resistor R6.
7 to the base of transistor T3.

The collectors of each of the transistors 'r4F T3 and T2 are connected to the power supply V through the thread removal coil WP1, the brake coil BR, and the clutch coil CL, respectively.

With the above configuration, when the command front pedal switch LSW is turned on, the output of the OR circuit OR2 becomes H level, and at this time, if the command road switch TSW is off, the NAND circuit AND output is turned on. is at H level, 5-DR which is the output of AND circuit AND6(7)
The IVE signal becomes H level, the output port C of the speed control circuit SPC becomes effective, the clutch coil CL and the brake coil BR are controlled by the output of the speed control circuit SPC, the sewing machine speed is kept constant, and the sewing machine SM is driven. Continue to do so.

At this time, if the command road switch TSW is at H level due to a failure, both NAND AND circuit AND1 will be at H level and the output will be at L level, so the AND
Circuit AND6. The outputs of AND7 and AND8 both become L level, and the AND circuit AND4. Since the output of AND5 is also set to L level, transistors T1. Since both T3 and T4 do not operate, the clutch coil CL,
The automatic thread trimming coil TRIM and thread removing coil WP do not operate.

In addition, the output of INV circuit ■NV3 becomes H level, and O
The output of the R circuit OR4 also becomes H level and the mono multi MM
operates for a certain period of time, the brake coil BR is energized, and the sewing machine SM is stopped.

As described above, the sewing machine SM completely stops.

Next, when the command road switch TSW is normal and is at the L level, the command front switch LSW is on, and the sewing machine SM
When the command front switch LSW is turned off while the is rotating, the 5-DRIVE signal that enables the speed control circuit SPC is turned off, but if there is no signal from the lower position detector DD and the signal is at H level, the AND The output of circuit AND2 becomes H level, the outputs of OR circuit OR2 and AND circuit AND6 are set to H level, and the 5-DRIVE signal is turned on at H level to drive the sewing machine SM, and when the lower position is reached, the output of lower position detector DD When becomes L level, AND circuit AND2
The output of
Since the output of the OR circuits OR1 and OR is set to the H level, the monomulti MM is turned on for a certain period of time to apply the brake and stop the sewing machine SM in the lower position.

Therefore, when there is no failure in the command front pedal switch LSW and the command road switch TSW is turned on, the flip-flop F
The Q output of F2 becomes H level, the output of AND circuit AND7 also becomes H level, and at the same time the automatic thread trimming coil TRIM is excited, the Q output of flip-flop FF1 also becomes H level, so AND circuit AND1 and OR circuit O
R2 and AND circuit AND6 become H level, and 5-D
When the RIVE signal becomes H level, the speed control circuit SPC
The output becomes valid and the sewing machine SM rotates.

Then, when the sewing machine SM rotates half a rotation, the upper position is reached and the output of the upper position detector UD becomes L level, and the output of the AND circuit AND1, the OR circuit OR2, and the AND circuit AN
Those of D6 are both at L level, and 5-DRIV
Since the E signal is at the L level, the driving of the sewing machine SM is stopped, and at the same time, the output of the NOR circuit NOR is at the H level.
The output of OR cycle 90R1, OR, also becomes H level, and the brake operates for a certain period of time to stop the sewing machine SM at the upper position.

At the same time, the flip-flop FF2 is reset and the Q output becomes L level, so the automatic thread trimming coil TR
IM excitation disappears.

In addition, the output of the AND circuit AND and the flip-flop F
Since the output of F1 becomes L level, the NOR circuit N0R
As the output of the AND circuit AND8 becomes H level, the first sweep coil WP is also energized in synchronization with the brake to sweep away the thread cut by the thread cutter.

In this case, if the command front switch LSW fails and
Considering the case where the command road switch TSW is turned on, the NAND AND circuit AND
1 becomes L level, and the AND circuit AND6. AND7
Since the output of AND8 is set to L level and the output of OR circuit OR4 is set to H level, automatic thread trimming coil TRIM
.

Both the thread removal coil WP and the clutch coil CL are prohibited from operating, and the brake coil BR is energized for a certain period of time to safely stop the sewing machine SM.

Therefore, dangers such as needle breakage do not occur at all.

The above description is based on a case where the so-called command front pedal and road switches LSW and TSW are out of order, but the above explanation is exactly the same in the case where there is a failure due to wire breakage, noise, or the like.

As described above, according to the present invention, it is possible to prevent malfunctions that occur when the command switches of the sewing machine SM, such as the command front pedal switch LSW and the command road switch TSW, fail or are subject to disconnection or noise. This can protect workers from dangers such as needle breakage.

Therefore, the part indicated by the broken line in FIG. 3 corresponds to the protection circuit PRC according to the present invention, and another embodiment in which this part is taken out will be explained next using the one shown in FIG. .

Note that each point from A to No. 4-J indicates the same wiring as the same reference numerals in FIG.

That is, the embodiment shown in FIG. 3 described above (in this case,
As soon as the faulty command front switch LSW and command road switch TSW were resolved, the circuits returned to normal.
In the embodiment shown in FIG. 4, once the command front switch LS
When W and command road switch TSW are both turned on, A
ND circuit AND.

The output of the AND circuit A becomes H level, flip-flop FF3 is set, and the output Q remains L level.
ND6. The outputs of AND7 and AND8 remain at the L level and continue in this state, so the automatic thread trimming, thread sweeping, and clutch coil excitation continue to be prohibited, and at the same time, the Q output of flip-flop FF3 becomes H. To maintain the level, transistor T5 is turned on and alarm device B
This notification is made by turning on ELL.

To return to this state, press the reset switch RESET or press the R
This is done by applying the ESE signal to the reset terminal R of flip-flop FF3.

Therefore, in the embodiment shown in FIG. 4, it is possible to ensure the safety of the workers and to notify the workers of the abnormality.

Also, even if the failure suddenly returns, 1. This also prevents the sewing machine from being driven and becoming dangerous.

Furthermore, what is shown in FIG. 5 and FIG. 6 relates to other embodiments.

Note that the same reference numerals as in FIGS. 3 and 4 indicate the same operations.

That is, the control circuit shown in FIG. 5 includes a microcomputer MC (hereinafter abbreviated as microcomputer MC).

) is used. Inside the illustrated microcomputer Me,
It is composed of a central processing unit, a data memory (partly RAM), a program memory (partly ROM), etc., and can be used with either a multi-chip or a single chip.

Inputs include a command front switch LSW, a command road switch TSW, and an upper/lower position detector UD-DD, which are similar to those shown in FIG.

The outputs are also the same as in Fig. 3, including the output port of the speed control circuit SPC, a 5-DRIVE signal that enables C, a fixed time brake signal 5-BRAKE, an automatic thread trimming signal S-TRIM,
5-BEL driving thread removal signal s-wp and alarm device
It is an L signal.

Moreover, FIG. 6 is a flowchart explaining the operation of the microcomputer MC.

That is, to explain when the command front pedal switch LSW and the command road switch TSW are normal, start, take in LSW as input with LSW READ, then check LSW, and if LSW is on,
Load TSW and check.

TSW is off now, so go to NO and DRIV
The sewing machine is driven by outputting the E signal and validating the speed control signal.

This time, to check that the LSW is turned off,
Take W and check.

When the LSW turns off, use DOWN READ to capture and check the lower position signal, and continue checking until the lower position is reached.

When the lower position is reached, the DFtIVE signal is turned off to stop driving the sewing machine, and at the same time, the BRAKE is turned on.

When the BRAKE time reaches the set value, the BRAKE
E turns off, returns to the initial state, and checks the LSW.

When LSW is off and TSW is on, LSW=ON becomes N.
Pass through O, read TSW with TSW READ, and read TS
Since W20N becomes YES, output the D RI VE signal to drive the sewing machine and check the lower position.

If it is in the lower position, DOWN2ON becomes YES and the automatic thread trimming signal TRIM is turned on, and the upper position is checked.When the sewing machine rotates half a turn and reaches the upper position, UP=ON becomes YES and the automatic thread trimming signal is activated. TRIM is turned off, and the brake signal BRAKE and thread removal signal wp are turned on.

If the set time elapses, the brake signal BRAK will be activated.
E: The thread removal signal WP is turned off, the sewing machine returns to the initial state δ, and checks the LSW.

Now, if the TSW remains on due to a failure, the LSW will turn on during the LSW check and the LSW will turn on.
SW=ON becomes YES, then TSW is read with TSW READ, and TSW=ON becomes YES, so D
RIVE, TRIM.

Turn off each signal of WP and output the brake signal BRAKE.

The alarm signal BELL is turned on, and the brake signal BRAKE is turned off after a certain period of time.

Next, the RESET signal is taken in and this state is maintained until the RESET signal is received.

Therefore, safe operation by preventing command switch failure, wire breakage, noise, needle breakage, and other dangers is exactly the same as in the examples shown in FIGS. 3 and 4.

Furthermore, what is shown in FIG. 7 is a modified example of the RESET part indicated by the broken line in the one shown in FIG. 6. In the one shown in FIG. In what is shown in the figure, LSW, TSW
This example shows an example of a mode in which the system is immediately restored once the failure has been cured.

Although the above explanation has been about the electromagnetic clutch type sewing machine shown in Fig. 1, sewing machines that control a so-called DC machine can operate in exactly the same way if the clutch signal is used as the control signal for the DC machine. It is possible to obtain similar effects.

Taking all of the above into consideration, the present invention can prevent dangers such as needle breakage and malfunctions due to command switch failure, wire breakage, noise, etc., and enables safe sewing machine control. Therefore, it can be said to be an outstanding invention in terms of its practical effects, such as ensuring safety and ensuring reliable operation.

[Brief explanation of drawings]

Fig. 1 is a schematic configuration diagram of an electromagnetic clutch type sewing machine, Fig. 2 is a conventional sewing machine control circuit, Fig. 3 is a control circuit showing one embodiment of the present invention, and Fig. 4 is another embodiment. The control circuit shown in FIG. 5 is an embodiment of the present invention! FIG. 6 is a flowchart explaining the operation of the microcomputer, and FIG. 7 is a partial flowchart of the microcomputer according to another embodiment. MOTOR...Motor, SM...Sewing machine, CL...Clutch coil, CLB...
...Clutch plate, CLM...Clutch friction plate,
BRM・・・Brake friction plate, BR・・・・・・
Brake coil, UD...Upper position detector, DD
...Lower position detector, LSW...Finger full front switch, TSW...Finger) passage switch,
FP...foot pedal, T-G...finger speed generator, FF1~FF3...flip flop, AND1~AND,...AND circuit, OR1
~OR4...OR. Circuit, NANDl...NANDAND circuit R1
~N0R2...NOR circuit, ■Nv1~1Nv
3...INV circuit, T1-T,...transistor, TFtIM...automatic thread trimming coil, WP...thread removal coil, BELL...・
・Alarm device, R1 to R0...Resistance, RESET
...Reset switch, SPC ... Speed control circuit, PRC ... Protection circuit, 5-DRI
VE... Speed control enable signal, MC...
microcomputer.

Claims (1)

[Scope of Claims] 1. A sewing machine that is equipped with a mechanism that drives a sewing machine using a motor, a mechanism that stops the sewing machine using a brake, an automatic thread trimming mechanism that automatically trims threads, and a foot switch that issues commands to the sewing machine. In a device in which each mechanism is controlled by electric signals, it is not possible that the front pedal signal, which gives a drive command to the sewing machine by the front pedal of the foot switch, and the road signal, which gives an automatic thread trimming command due to the road, are turned on at the same time. A safety protection system for an electric sewing machine is characterized in that the operation of a sewing machine drive mechanism and an automatic thread trimming mechanism is immediately disabled when a state in which the sewing machine is not in use is detected. 2. An electric sewing machine according to claim 1, wherein the mechanism for driving the sewing machine and the automatic thread trimming mechanism are disabled, and at the same time, the mechanism for stopping the sewing machine for a certain period of time is operated to stop the sewing machine. Safety protection method. 3. According to claim 1, when a situation in which a front pedal signal and a road signal are turned on at the same time, which should not occur in the first place, is detected, the operation of the sewing machine drive mechanism is disabled and an alarm device is activated. A safety protection system for electric sewing machines. 4. An electric sewing machine as set forth in claim 1, wherein recovery from an originally impossible state in which a front pedal signal and a road signal are turned on at the same time is performed by a reset signal or a command from a reset switch. Safety protection method.