JPS6027315B2 - Fixed position stop device for electric sewing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a needle positioning stop device for an electric sewing machine, which includes a declutch mechanism that engages and disengages the transmission of the driving force of the sewing machine motor to the upper shaft of the sewing machine, and a declutch mechanism that stops the sewing machine at a specified needle position. Effectively combines the needle positioning/false stopping mechanism and electrical control such as operating the sewing machine at a low speed necessary for stopping the sewing machine prior to stopping the needle by using an electric timer in conjunction with these mechanisms, and connecting power to the sewing machine motor. As a result, the present invention aims to provide a needle localization counterfeiting device that has high needle localization layer stop precision and safety in its operations.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram of a sewing machine equipped with a device of the present invention, in which 1 is the sewing machine body, 2 is a pulley, and the driving force of the sewing machine motor (not shown) is connected to the first belt 3, intermediate pulley 4, and second belt 5.

Reference numeral 6 has an upper shaft to which a stopping gum 7 is fixed, and the stopping cam rotates in the direction of the arrow in the figure when the corner 10 of the locking pawl 9 engages with the locking portion 8. The locking pawl 9 is pivotally supported by a screw 11 and the corner 1
0 is biased counterclockwise by a spring 12 in order to reposition it out of the rotational orbit of the locking portion 8.

Reference numeral 13 denotes an electromagnetic solenoid which is de-energized during normal operation of the sewing machine, so that a declutching pupil (not shown) transmits the rotation of the pulley 2 to the upper shaft 6. When excited, the plunger 14 is attracted and acts as a declutching device to release the rotation of the pulley 2 from being transmitted to the upper rock 6. At the same time, the corner 10 of the locking pawl 9 is moved by the spring 12 via the ring 15.
The stop cam 7 is moved onto the rotational trajectory of the locking portion 8 against the force.

FIG. 2 shows an electric control circuit showing an embodiment of the present invention, and in the figure, V is an AC power source, and a sewing machine motor M, speed control circuit sections S and C, and the power source are connected in series. In the speed control circuit sections S and C, thyristors SCR3 and SCR2 are connected in antiparallel to each other, and trigger transistors Tr. The diode ○,,D is connected to the emitter of
Each gate circuit via thyristor SCR, SC
The mutual trigger sensitivities of R2 are made different, for example, as the emitter level of the transistor Tr becomes higher, the thyristor SCR becomes conductive at first, and the conduction angle gradually becomes larger.
Next, thyristor SCR2 is also made conductive, thereby shifting from half-wave phase control to full-wave phase control, enabling a wide range of speed control. Capacitors C, C2 and resistors R3 and R4 are used to prevent ignition of these thyristors and to protect the gate.

Diodes D3 to D6 form a full-wave rectifier circuit and are smoothed by capacitor C3, and Zener diode ZD compensates for power supply voltage fluctuations and is connected to controller CON via resistor R5.
It provides the base current and collector current of the transistor Tr through T, etc., and also supplies a control current to a first timer T, a second timer L, etc., which will be described later. The controller C
The ONT is equipped with a switch section SW that is operated by foot or manual operation, and the bush piece 1 connected to the DC side of the rectifier circuit is always on the contact a side and becomes the contact b side when the sewing machine is operated.

The contact a side is connected to the base of the transistor Tr through a semi-fixed resistor R6 and a diode D7 for setting the sewing machine to constant low speed rotation when stopping the sewing machine, but the contact a The transistor Tr2 connected to the controller CONT is in a conductive state as described later when the controller CONT is not operated.
No current is supplied to the base. contact b
are variable resistor VR and diode D in the controller,
. Similarly, the transistor Tr. The variable resistor reaches its maximum value when the reinforcement piece 1 is set to the contact point B side in the first operation by foot pedal or manual operation, and at that time, the motor M is stopped or set to the minimum rotation. The resistance value can be gradually reduced by pressing the pedal, etc., until the maximum rotation is reached. capacitor C4,
Diode D,. are used to prevent malfunction of the transistor Tr, and to prevent reverse voltage between the base and emitter, respectively; resistor R7 and semi-fixed resistor R8 are used to set the sensitivity of the transistor; and resistor R
9 is a load resistor for taking out the trigger voltage of the thyristors SCR, SCR2. The resistor VR and the diode D. . The connection point is a diode D,2, and a resistor R, connected in parallel with each other. and a first timer T, via a capacitor C6. The first timer has a capacitor C6 and a Zener diode Z12 for charging to a constant voltage when the straw piece 1 of the switch SW is on the contact b side, and has resistors R, . A base current is applied to the transistor Tr3 through the transistor Tr3 to generate a collector current through the diode D, 3 connected to the power supply V, and the resistors R, 2, R, 6, and even after the contact b side is opened, the capacitor C6 and Resistance R
、． The transistor is made conductive for a certain period of time based on the discharge time constant determined by , and the base current of the transistor Tr2 through the resistor R and 4 is set to 0 during that period, thereby making the transistor non-conductive. R,6 is a sensitivity setting resistor of the transistor Tr3. The capacitor C5 is used to equivalently short-circuit the resistors R and o immediately after the contact b side is closed, thereby immediately making the transistor Tr3 conductive. R, 6 and R, 7 are transistors T, respectively.
The capacitor C7 and the Zener diode ZD3 constitute a constant voltage power supply circuit of the transistors Tr2 and Tr3. The contact a is connected to the second timer T2 at the junction between diodes D8 and D9. In the second timer, a discharging resistor R,6 is connected to a capacitor C8, and when the contact a is connected, the capacitor is not charged, and when the contact is closed, the transistor Tr2 is connected to the capacitor under the condition that it is non-conducting. With a charging constant determined by C8 and the semi-fixed resistor 9, the voltage of the diode 4 is reached after a certain period of time, after which the base current is supplied to the transistor Tr4. The collector of the transistor is the diode D,3 and the resistor R2. and the emitter is connected to the power supply V through the diode D. 4 to the gate of thyristor SCR3. R
3 and ZD4 are the sensitivity setting resistor and protection diode of the transistor Tr4, respectively, and R22 is the gate protection resistor of the thyristor SCR3. SOL is an electromagnetic solenoid connected between the flea sources V via a thyristor SCR3. D and 6 are diodes for shorting the reverse voltage of the thyristor. In the above configuration, when the power supply V is turned on, the controller CONT has the bush piece 1 on the contact a side, no voltage is applied to the first timer T, and no base current is applied to the transistor Tr3. Therefore, the transistor Tr2 is conductive and does not provide the base current of the transistor Tr, so the thyristor SC
R, , SCR2 are all non-conductive, and motor M is stopped.

Further, since no voltage is applied to the second timer T2 and the electromagnetic solenoid SOL is not excited, the upper shaft 6 is in a coupled state with the pulley 2. Next, when the controller CONT is depressed, the bush piece] becomes the contact b side and the transistor Tr
A current is supplied to the base of the transistor, and as the amount of depression increases, the resistance value of the variable resistor VR decreases to increase the collector current of the transistor.First, half-wave phase control is performed by the thyristor SCR, and then Thyristor SCR,,S
Full-wave phase control is performed by CR2, and the speed of the motor M is controlled from low speed to high speed.

On the other hand, since the contact b is closed, the first timer T makes the transistor Tr3 conductive, so that the transistor T
Make r2 non-conductive.

Next, when the operation of the controller CONT is released in order to stop the sewing machine, the saddle piece 1 becomes the contact a side, and from this point on, the first timer T continues discharging the capacitor C6 and the transistor Tr2 is discharged at a constant value set by the timer. Make time nonconductive. Therefore, during this period, a constant current is supplied to the base of the transistor Tr via the resistor R6, and the motor M rotates at a constant low speed. Meanwhile, during this time, the second timer T2 turns on the transistor Tr4 after a certain period of time set by the timer has elapsed, so that the thyristor S
CR3 is made conductive and an excitation current is applied to the solenoid SOL to release the upper shaft 6 from the pulley 2, and at the same time move the corner 10 of the locking pawl 9 into the rotation orbit of the locking portion 8 of the stopping cam 7. Therefore, the sewing machine stops at the needle position within one subsequent revolution of the upper shaft 6 of the sewing machine. When the set time of the first timer T has elapsed, the transistor Tr3 becomes non-conductive and the transistor Tr2 becomes conductive, so that the base current of the transistor Tr is not supplied and power is no longer supplied to the motor M. Since no voltage is applied to the timer L, both the transistor Tr4 and the thyristor SCR3 are rendered non-conductive, and the solenoid SCL is de-energized.The upper shaft 6 is coupled to the pulley 2, and the locking pawl 9 is moved out of the rotation orbit of the stopping cam 7. move it to Next, when the controller CONT is depressed and released, i.e., the bush piece 1 is quickly and repeatedly operated from contact a←→contact b, the capacitor C is transferred to contact a.
Immediately activate the first timer T through the circuit 5, make the transistor Tr2 non-conductive, rotate the motor M at low speed, operate the solenoid SOL at the time of transition to the subsequent contact a, and stop the needle positioning. Then, perform one intermittent stitch. As described above, according to the present invention, when the power is turned on, the normal speed control circuit, the low-speed rotation circuit for direct stop of needle positioning, and the solenoid circuit are all inactive, and normal speed control is performed by operating the controller. When stopping by releasing the controller, the hands are operated at low speed for a certain period of time and the hands are mechanically stopped after the transition to low speed operation, so the shock at the time of stopping is small, the accuracy of the stopping position is high, and After stopping, the low-speed operation circuit and solenoid circuit are reliably cut off unless the controller is operated again, so after stopping, you can freely operate the pulley to move the needle position, etc. Furthermore, even if the sewing machine is forcibly locked due to thread tangle, etc., even if it is not the needle positioning layer, by releasing the controller, the power supply to the motor will stop after a certain period of time, so there is no risk of burnout. There is no risk of accidents, the control circuit is relatively simple, the number of lead wires for the controller is small, and the controller setting position can be foot-operated, manual, or built into the sewing machine head. Furthermore, since it does not use a mechanism for adjusting the stop timing using a mechanical timer or the like, it has many advantages such as a simple configuration.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of a sewing machine equipped with the apparatus of the present invention, and FIG. 2 is a control circuit diagram showing an embodiment of the present invention.

In the figure, M is a sewing machine motor, SW is a switch member, resistance horse is a main element of a low speed rotation setting section, T, T2 are first and second time setting circuits, and SOL is an electromagnetic solenoid.

traditional map N total

Claims (1)

[Claims] 1. A sewing machine motor that drives the upper shaft of the sewing machine, a declatch mechanism that connects and separates the upper shaft and the sewing machine motor, and a declatch mechanism that moves the needle of the sewing machine to a specified position when the upper shaft and the motor are separated. A sewing machine equipped with a fixed position stop mechanism that can stop the sewing machine at a fixed position, a switch member that switches between rotational speed control and stopping operation of the sewing machine, and a low speed rotation setting section that can be set effectively when the switch member is on the stopping operation side. , an electromagnetic solenoid for enabling and disabling the declatch mechanism and the stop mechanism; and an electromagnetic solenoid that enables the low speed rotation setting section for a first predetermined period of time from the time when the switch member switches from the speed control side to the stop operation side. and a first time setting circuit that operates the electromagnetic solenoid to stop the declutching mechanism and the stop mechanism in the fixed position after a second predetermined time has elapsed from the point in time within the first predetermined time. and a second time setting circuit that is activated to enable the sewing machine and returns to drive the sewing machine again on the condition that the first predetermined time period has elapsed.