JPS6223595B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a sewing machine that increases or decreases the amount of electricity supplied to a sewing machine motor in response to the amount of operational displacement of a pedal in one direction, thereby changing the driving speed of the motor. Based on the information in the electrical storage section that stores information such as direction, motor drive speed, etc., and operation information that controls the operation mechanisms such as thread cutting and presser foot lifting, these operations are controlled in relation to pedal operation. This invention relates to a control device for a sewing machine.

Conventionally, by pressing the pedal forward from the release position (intermediate position), the amount of electricity supplied to the motor is increased or decreased in proportion to the amount of pedal displacement, and sewing is performed at the desired motor speed by the operator's pedal operation. At the same time, the motor was stopped by returning to the release position, and the thread trimming device was activated by pressing the pedal backwards, and the motor was stopped at a predetermined rotation angle of the main shaft. Sewing information such as number of stitches, cloth feeding direction, and motor drive speed range suitable for the seam forming section is stored in an electrical storage unit such as a microcomputer, and the motor is driven within the memorized drive speed range by pedal operation. Sewing machines have been developed that automatically stop the motor regardless of pedal operation when a predetermined stitch formation is completed, and operate mechanisms such as thread trimming devices at predetermined times.
The circuit that controls the sewing machine motor is built into a circuit that has a memory section and is not independent, so if the memory section malfunctions, the motor cannot be driven even if the pedal is operated, and the memory section cannot be used. This has resulted in drawbacks such as the ability to perform conventional normal sewing operations, and the sewing machine to become completely inoperable, resulting in a significant drop in work efficiency.

This invention aims to eliminate the drawbacks of the above-mentioned conventional devices.

To explain an embodiment of the present invention with reference to the drawings, a sewing machine 1 has a pulley 2 fixed to a main shaft (not shown).
is connected to the electromagnetic clutch motor 3 by a belt 4, and includes a position detection section TG that detects a predetermined rotation angle of the main shaft and generates a position signal, and a speed detection section TG that detects the rotation speed of the main shaft and generates a voltage proportional to the speed. (FIG. 2) is arranged between the main shaft and the sewing machine 1. Further, the head of the sewing machine 1 is provided with an operation button 6 for reverse stitching and a magnet 7 for raising and lowering the presser foot, and a magnet 8 for thread trimming and a magnet 9 for reversing the feed are provided below the bed.

The pedal 10 can be operated forward and backward from the release position (intermediate position), and has a speed setting section that divides the output of the speed detection section TG in proportion to the amount of displacement of the forward operation.
PS (Fig. 2), start switch LS (Fig. 2) which generates an L level signal in connection with forward operation to the initial position, and thread trimming switch which generates a thread trimming signal in connection with backward operation. (not shown)
A pedal sensor 11 is provided.

Next, referring to FIG. 2, the speed control circuit SC and sewing control circuit NC will be explained.

The sewing control circuit NC has a memory section (microcomputer) MC that includes RAM, ROM, and CPU, and a setting section MS stores setting signals such as the number of stitches generated by the operator's selection operation from outside the sewing machine 1.
Make the MC remember it as information. The memory unit MC reads out the stored information every time a position signal is generated and sends it to terminal a~
A command signal of L level is generated at k. Terminals a~c
generates an operation command signal for each magnet 7 to 9,
Terminals d to i generate a speed command signal to set the upper limit of the motor drive speed corresponding to stitch formation, terminal j generates a drive command signal to drive the motor, and terminal k stops the motor. Generates a stop command signal. Resistor groups E having different resistance values are connected to the terminals d to h through buffers Bd to _Bh , and the voltage generated by the speed detection section TG is divided by different ratios.

The comparator circuit _C1 compares the voltage of the speed detection section TG divided by the resistor group E with the voltage of the speed setting section PS, and generates an H level signal when the voltage of the setting section PS becomes lower than the detection section TG. do. Comparison circuit C ₂ ,
_C3 connects the series resistor of the reference circuit F provided in the speed control circuit SC and the non-inverting input, and compares it with the voltage of the speed detection section TG divided by the resistance group E, and the comparison circuit _C2 detects When the part TG is higher than the l point of the reference circuit, the output is at H level, and the comparator circuit _C3 is the detection part.
When TG is lower than point m of the reference circuit, the output is at H level.

In the speed control circuit SC, BR is a brake magnet for the motor 3, and CL is a clutch magnet, each of which is energized when the input is at L level. ZSW is a selection switch for using (x) or not using (y) the memory section MC, and OM is a one-shot multivibrator that generates an "H" output for a set time when a rising signal is input to the B input terminal. , is cleared when L level is input to the clear terminal.

Comparison circuits C ₄ and C ₅ connect each resistor of the reference circuit F to the non-inverting input, and compare the voltage of the detection section TG divided by _the speed setting section PS. When the voltage _of
When the voltage is lower than point m, the output is at H level.

Note that G ₁ to G ₁₄ are IC NAND gates.

The present invention has the above-described configuration, and will be described with the selection switch ZSW closed to the storage unit MC usage (x) side. The operation signal from the setting circuit MS is stored in the memory unit MC, and when the pedal is operated forward, an L level signal is generated from LS at the beginning of the operation, and the memory unit MC sets terminal i to L, terminal j to L, terminal By setting k to an H level output, the brake magnet BR and clutch magnet CL are controlled so that the drive speed of the motor 3 corresponds to the outputs of the terminals d to h. That is, due to the L output of the terminal i, the gate G ₂ becomes an H output, the gate G ₅ is opened, the gates G ₆ and G ₇ become an H output, and the resistor group E
When _the voltage of the detection unit TG divided by
becomes H output and gate G ₃ becomes L output, gate G ₈ becomes H output, G ₁₂ becomes L output, G ₁₄ becomes H output and gate G ₁₅ becomes L level, so the brake magnet BR is energized and motor 3 is braked, and the detection part TG is activated due to the decrease in rotational speed.
When the voltage of the reference circuit F becomes lower than point m of the reference circuit F, the comparator circuit _C3 becomes an H output and the gate _G4 becomes an L output, which causes _G9 to become an H output and _G13 to become an L output, so that the clutch The magnet CL is energized and the motor 3 is driven at a nearly constant speed, and when a predetermined number of stitches are formed, the terminal k of the memory section MC becomes an L output, and as a result, the gate _G13 becomes an H output and the gate
_G14 becomes H output and closes _G15 , making brake magnet BR energized and clutch magnet CL deenergized.

The selection switch can be used when the storage MC fails, etc.
Move ZSW to y side. LS by forward operation of the pedal
Then, an L level signal is generated, gate _G10 becomes H level, gate _G13 is set to L level, clutch magnet CL is energized, motor 3 is driven, and the speed setting section PS sets the speed. When the voltage of the detected part TG is higher than point I of the reference circuit F, the comparator circuit _C4 becomes an H output, the gate _G6 becomes an L output, the gate _G8 becomes H, the gate _G12 becomes L, and the gate _G14 becomes an L output. H, gate G ₁₅ outputs L, so even if brake magnet BR is activated, the motor is braked, and when the motor decelerates and the detection section TG voltage falls below point m of reference cycle F, comparator circuit C ₅ becomes an H output, gate G ₇ becomes an L output, gate G ₉ becomes an H output, and gate G ₁₃ becomes an L output, so the clutch magnet CL is energized and accelerates the motor. When the amount of forward operation of the pedal is increased, the partial pressure of the setting part PS changes and the voltage decreases, and the comparator circuit _C5 becomes an H output, energizing the clutch magnet CL and accelerating the motor 3. Conversely, when the amount of forward operation of the pedal is decreased, the voltage from the setting part PS increases, the comparator circuit _C4 becomes an H output, energizes the brake magnet BR, and the motor 3 decelerates. Therefore, the motor 3 is driven at a speed proportional to the amount of pedal operation. When the pedal is released, LS outputs H, and the rising signal causes one-shot OM to output H at the Q terminal for a predetermined set time, set gate G ₁₁ to L, output G ₁₃ and G ₁₄ to H, and output clutch mag. Deenergize the net CL, energize the brake magnet BR, and suddenly stop the motor 3.

As described above, according to the present invention, the control circuit NC supplies electricity to the motor in proportion to the one-way operation of the pedal 10 so that the pedal 10 rotates within the speed range based on the information in the memory section MC; A control circuit SC that supplies electricity to the motor in proportion to one-way operation is provided separately, and one of the circuits is selectively connected to the motor, so even if the memory unit fails, the motor will continue to operate normally. Sewing work can be performed by being driven by pedal operation.
Since the sewing machine can be operated, the effect of improving work efficiency can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the control device of the sewing machine of this embodiment, FIG. 2 is an electric circuit, and FIG. 3 is a time chart of speed control.

Claims (1)

[Scope of Claims] 1. A driving body 3 connected to the main shaft and electrically changing rotational speed; a pedal 10 operable in at least one direction from the release position; and a pedal 10 that is proportional to the amount of displacement of the pedal in one direction. The first control circuit SC changes the driving speed of the driving body by changing the speed of the driving body, and the electrical storage unit stores the speed range of the driving body suitable for the length or direction of the seam line as information. A second control circuit NC that changes the drive speed of the drive body so that it rotates within the speed range according to the information in the storage unit in proportion to the amount of rotation, and a second control circuit NC that changes the drive speed of the drive body so that it rotates within the speed range according to the information in the memory unit, and a second control circuit NC that changes the drive speed of the drive body so that it rotates within the speed range according to the information in the memory unit, and the drive body is operated to either the first control circuit or the second control circuit. A sewing machine control device equipped with a selection means ZSW to be connected and a