JP2519967Y2 - Speed control device for sewing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a speed control device for a sewing machine.

(Problems to be Solved by Prior Art and Invention) In a conventional speed control device for a sewing machine (hereinafter abbreviated as a controller) by phase control, a switch for a circuit breaker is not operated at all without operating a tread of the controller. When the sewing machine is stopped, the power supply voltage is applied to the electronic components of the phase control element of the main circuit and the trigger gate circuit of the phase control element unless the power plug is pulled out. Therefore, in this case, when a semiconductor or electronic component of each circuit causes a component failure such as a short circuit, a current flows through the electric motor of the sewing machine, and at that time the user is working at the needle, and no one is near the sewing machine. Even at that time, the sewing machine motor was suddenly turned around, which was extremely dangerous.

In addition, electronic components such as semiconductors are generally handled as short-circuit fault components even in terms of electrical safety standards. For this reason, in order to prevent a fault current from flowing in the controller circuit even if a failure occurs in an electronic component when the controller's tread is released, conventionally, the circuit is linked to the controller's tread release operation on the power supply side of the circuit. A switch to cut off is provided. However, in this case, the current of the main circuit flowing through the winding of the motor is directly switched on and off by a switch, so sparks are generated between the contacts when the switch is opened and closed, and the life of the switch contacts is significantly impaired. When a spark is generated, a very high voltage is generated, which is applied to the phase control element and the life of the element is impaired, leading to defective failure of the element.
Furthermore, this high voltage is a shocking discontinuity noise (hereinafter abbreviated as click noise) due to a shocking rise due to sparks.
However, the conventional phase-controlled controller has a defect that defects and defects are generated along with the operation of the tread.

(Means for Solving the Problem) Therefore, in the present invention, as the first means, the main circuit side including the power source of the circuit for performing the phase control and the load circuit in which the electric motor is connected to the phase control element as the load and the phase control A circuit breaker S ₁ and S ₂ for opening and closing each circuit is provided on the gate circuit side for triggering the device in association with both circuits, and a switch actuating member of the circuit breaker S ₁ of the main circuit among the circuit breakers. A speed control device for a sewing machine, in which an operating load device for delaying the shutoff is attached to the sewing machine, and a switch actuating member of the shutoff device of the main circuit is a projecting arm for leading the closing circuit for leading the closing circuit as the next means. It is provided.

(Operation) When the tread of the controller is released to break the circuit, the circuit breakers S ₁ and S ₂ of the main circuit and the gate circuit work together to operate the respective switch actuating members. At this time, the gate circuit immediately cuts off the circuit as it is, and the main circuit mounts an operation load device for prolonging the operation execution time on the switch operating member to delay the circuit cutoff time from the gate circuit. When the gate circuit is cut off, a current is flowing through the main circuit due to the inductance of the motor winding, and the circuit break of the main circuit is delayed by a preset operating load device until the current becomes zero. Therefore, the main circuit is shut off when no current is flowing. On the other hand, when the step board of the controller is stepped on to close the circuit, the main circuit is first closed before the gate circuit, and then the gate circuit is closed. For this purpose, the switch actuating member of the main circuit is actuated first as a projecting arm for actuation of the preceding closing circuit. As described above, when the main circuit is closed, the gate circuit is opened, so that the phase control element of the main circuit is not triggered and the main circuit is closed in the state where the current is zero. After that, a minute signal current for triggering the phase control element flows through the gate circuit, which is switched, by a closed circuit.

Embodiment 1 An embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows a conventional controller in which a switch S is a gate circuit-trigger for a triac composed of resistors R ₁ and R ₂ , capacitors C ₁ and C ₂ , and a diac DIAC, and a main circuit-a phase control element of a triac TRIAC and an electric motor M. Trigger stabilizer circuit for the motor and the phase control element-Open and close the AC power supply for the Triac guarantee of the triac consisting of the capacitor C ₃ and the resistor R ₃ .

The opening / closing of the switch S and the phase adjustment by the resistance R ₂ are performed by operating the tread plate of the controller. This will be explained with reference to FIG. 6. When the controller tread is released when the sewing machine motor is stopped and the tread is depressed, and when the switch S is closed at the phase of the power supply voltage t ₁ , the voltage v is applied to the electric motor M and the current i flows, and the tread is further continued. By depressing, the resistance R ₂ is adjusted and the phase t ₁ with respect to the power supply voltage advances and the voltage v and the current i
The switch S opens when the tread plate is depressed and the phase t _{1 of the} power supply voltage is exceeded. This switch S
Is still closed at the phase t ₁ , the current i continues to flow due to the inductance of the electric motor M even when the voltage v is zero and continues to the phase t ₂ . When the switch S is opened and closed, there is chattering of the switch (vibration at the time of switching), so this current i is turned on and off to generate a spark between the contacts of the switch S.

Figure 2 is a controller according to the present invention, the main circuit and the (abbreviated as switches S ₁ following switches S ₁₎ circuit breaker apparatus S ₁ of the opening and closing of the AC power supply of the gate circuit and the phase control ballast circuit and the gate circuit switch A circuit breaker S ₂ (switch S ₂ hereafter abbreviated as switch S ₂ ) is provided, and these are switches for pressing the switch operating members E, e by the pressing elements F, f. The switch S ₁ and the switch S ₂ are interlocked with each other, and the opening and closing of the switch and the phase adjustment by the resistor R ₂ are performed by operating the step board of the controller. In the switch actuating member of the switch S ₁ , the abutting portion R of the pusher F is used as a protruding closing actuation arm, and a weight W is attached to the tip end thereof as a switch actuating load device. When the tread plate is depressed after the tread plate of the controller is released, the switch operating member E of the switch S ₁ moves as indicated by A, B and C. At this time, in the switch S ₂ , the pusher f also pushes the contact point r of the switch actuating member and moves a, b, c. When the switch S ₂ is in the b position, the switch S ₁ is pushed earlier than the switch S ₂ by the protrusion of the abutting portion R and is closed earlier to the B position. At this time, since the gate circuit is opened by the switch S ₂ , the current for triggering the triac does not flow, so that the main circuit does not trigger the triac either.
Since the triac is not triggered, there is no conduction between the motor M and the AC power supply. Therefore, the switch S ₁ is closed when no load current is flowing through the electric motor M, and no spark is generated at the switch contact.

Further depressing the treadle switches S ₁ The direction of the switch S ₂ becomes the position of the C of protrusion of the arm protrudes pushed the abutment R switch actuating member E is at pushing element F is substantially flat across the switch contacts At the position of c, a closed circuit of both the main circuit and the gate circuit is formed. When the switch S ₂ is closed, a minute current for triggering the triac flows in the gate circuit, so that sparks are hardly generated at the switch contacts.

Next, when the stepping on the step plate of the controller is released, the switch S ₁ and the switch S ₂ move the respective switch operating members E and e to C, B, A and c, b, a. The switch S ₂ moves to the position of c immediately after the release of the tread and opens the gate circuit at the position of b on the way, but at that time, since the gate current is minute, almost no spark is generated between the switch contacts. After releasing the tread, the switch S ₁ has a weight W at the tip of the switch operating member E, so that the gravity load acts on the switch S ₁ so that the switch operating member E starts to slowly restore and then returns to the position B and further moves to the position A. Push the switch operating member E up to and return. Switch S ₂ is c
Immediately before leaving the position of, the voltage v conducted to the power source is applied to the electric motor M of the main circuit at the t ₁ phase in FIG. 6 and the current i flows to the t ₂ phase. Thus the main circuit even when the switch S ₂ is opened is a triac current i holding current t ₁ ~t ₂
It flows to the phase. Since the current disappears when the phase exceeds t ₂ phase, in the present invention, the switch breaking is delayed with respect to the switch S ₁ , and when the phase exceeds the phase t ₂ , the gravity load that opens the main circuit is applied to switch s ₁ . Switch operating member E
Since the weight W is attached to the tip of the switch to slow the switch operation as described above, no spark is generated when the switch S ₁ is opened.

(Embodiment 2) FIG. 3 shows a switch S ₁ for opening / closing a main circuit and a switch S ₂ for opening / closing a gate circuit according to the present invention, and the switch actuating member E of Embodiment 1 abuts the sliders F and f. The portions R and r are shown as protruding arms, and the pressers F and f of the first embodiment are the sliders F and f.

These sliders F, f slide on the switch actuating members of the switches S ₁ , S ₂ by operating the step board of the controller in conjunction with each other. Since these switch operations are the same as those in the first embodiment, the description thereof will be omitted.

(Embodiment 3) FIG. 4 shows the open / closed states of the main circuit opening / closing switch S ₁ and the gate circuit opening / closing switch S ₂ , showing one slider F.
Switch S ₁ is closed by pressing in the direction of the arrow, then switch S ₂ is closed and the rack attached to slider F rotates pinion P to change the resistance of R _2. Speed control. When the pressing force is released, the slider F starts to return by the force of the coil spring G, maximizes the resistance of R ₂ , opens the switch S ₂ and opens the switch S ₁ , and returns to the initial position. The operations and actions of the switches S ₁ and S ₂ are the same as those described in the first embodiment, and will be omitted.

Example 1 of Fig. 5 this invention, Example 2, shows the switching on and off of the switches S ₁ and S ₂ in the third embodiment, the switch S ₁ at time-to ₁ before the switch S ₂ is closed Close
At a subsequent time to ₂ , switch S ₂ is closed, this time when switching off the circuit, first switch S ₂ is opened at time t ₁ and then switch S ₁ is opened at time t ₃ and these times to ₁ , to ₂ corresponds to a phase indicated by the dotted line before the power supply voltage of Figure 6 is applied to the motor, and the time t _1, t ₂ of FIG. 5 is t ₁ ~ current is flowing in the electric motor in FIG. 6 Since it corresponds to the t ₂ phase, and therefore the time t ₃ when the switch S _{1 is} open in FIG. 5 exceeds the phase of t ₂ in FIG. 6, no current flows in the motor at this time. FIG. 7 shows the open and closed states of each switch.

(Effect) As described above, according to the present invention, the switch for the main circuit and the switch for the gate circuit are interlocked, the operation load device is attached to the switch operation member of the switch on the main circuit side, and the operation member is projected. By using the arm, a large load current of the motor is not turned on and off directly when opening and closing each switch, and therefore no significant spark is generated between the switch contacts. It is possible to construct a good speed control device that does not.

[Brief description of drawings]

FIG. 1 is a conventional controller, and FIG. 2 is the first and third embodiments.
FIG. 4 is a switch section of the second embodiment, FIG. 4 is a switch section of the third embodiment, FIG. 5 is a timing chart of switch opening / closing in the first to third embodiments, and FIG. FIG. 7 is an explanatory diagram showing voltage and flowing current, and FIG. 7 is an explanatory diagram showing open / closed states of the switch.

Claims (1)

(57) [Scope of utility model registration request] 1. A speed control circuit of an electric motor for controlling the speed of the electric motor by performing phase control of a voltage applied to the electric motor, including a load circuit in which the electric motor is connected as a load to a power source of the speed control circuit and a phase control element. Provided in conjunction with both circuits of the circuit breaker S ₁ and the circuit breaker S ₂ that open and close each circuit on the gate circuit side that gives a signal for triggering to the gate of the phase control element of the main circuit side and the load circuit, closing the switch actuating member of the circuit breaker apparatus S ₁ of the main circuit as well as attaching a working load device for interrupting the delay to switch actuating member of the circuit breaker apparatus S ₁ of the main circuit of the circuit breaker apparatus S _1, S ₂ A speed control device for a sewing machine, characterized in that it has a protruding arm for actuating a preceding closed circuit for preceding movement.