JPS5911742Y2 - Sewing machine controller - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a sewing machine controller that takes countermeasures against radio wave interference to radios, televisions, etc.

In a resistance wire type controller, sparks are generated when the current is turned on and off between the resistance variable slider and the resistance wire, and in a carbon pile type controller, sparks are generated between the resistance variable slider and the carbon pile. Sparks are generated between carbon piles and between carbon piles, and these sparks cause radio interference to radios, televisions, and various wireless devices.

Conventionally, it has been generally known to connect a preventive device such as a capacitor between the spark generating terminals of devices that generate sparks as described above to prevent sparks or prevent radio wave interference.

However, in the case of a controller for an electric sewing machine, simply installing a preventer between terminals that generate sparks is not desirable in terms of electrical safety.

In other words, if the controller is always energized if the prevention capacitor etc. is destroyed or conductive for some reason, the motor and controller will be energized when the sewing machine is not in use, and the controller will lose its ability to stop the motor. However, there are drawbacks such as the risk of abnormal heat generation of the motor and controller.

The present invention provides a controller for a sewing machine equipped with an protector, which eliminates the above-mentioned electrical risks and has the conventional prevention effect.

The embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, 1 is a power source, 2 is a sewing machine controller, 3 is a sewing machine motor, and 21 is a resistor (21) connected in series to the motor for controlling the motor speed. In this diagram, the resistance wire system is shown)
, 22 is a sliding contact for variable resistance that also serves as a contact switch; 2
3.24 is each terminal part, 25 is an insulating part, the terminal pair 23.24 is connected to each end of the power supply and the motor, and the contactor 22 is on the insulating part 25 when it returns naturally; A radio wave interference preventer 28 is connected between the first contact part 26 and the second contact part 27 adjacent to the insulating part, and
The resistor 21 is connected to the contact portion 27 .

The contact 22 is capable of sliding on the insulating section 25, the contacts 26 and 27, and the resistor 21.
6. 27, these contacts are simultaneously contacted to short-circuit the radio interference preventer 28.

In FIG. 2, instead of contacting the contact 27 due to its structure, the contact 22 contacts the vicinity of the connection point on the resistor 21 connected to the contact, thus making simultaneous contact with the contact 26 described above possible. .

In FIGS. 1 and 2 of the present invention described above, by stepping on the footboard (not shown) of the controller, the contact 22 of the controller 2 is moved from the insulating part 25 to the contact 26 . 27
The speed of the sewing machine motor 3 is controlled from low speed to high speed by sliding on the resistor 21 through the resistor 21, and the sewing machine is operated.

Further, by releasing the treadle, the contact 22 naturally returns to the insulating portion 25 and the sewing machine motor 3 stops.

Here, the contactor 22 short-circuits contacts 26 and 27 once when the sewing machine starts or stops, and then contacts 27 or 2.
6, and during operation transition, the contact 22 moves from contact 26 to contact 26 . When short-circuiting contacts 27 or during a stop transition, contacts 26 . 27 When contact 27 is opened from a short-circuited state, sparks are generated between contacts 26 and 27 as the motor current turns on and off, resulting in radio wave interference.However, radio wave interference between the terminals can be prevented. Vessel 2
8 absorbs the spark current at the time of the short circuit or open circuit, thereby preventing radio wave interference.

In addition, in FIGS. 1 and 2, the radio interference preventer 28 is connected to the contact 26.
．． 27, but it may be connected to the terminal 24 without being directly connected to the contact 27.

In the installation example of the radio wave interference preventer 28 as shown in FIGS. 3 and 4, which is commonly used in the past, the preventer 28 always connects to the sewing machine motor 3 (
In Fig. 4, since the power supply voltage is further charged through the resistor 21), in the event of an accident such as destruction of the preventer, the motor and the resistor become energized, and the controller stops the motor. This poses a risk of loss of power or abnormal heat generation of the motor or controller.

In the present invention, the contactor 22 is located at the insulating portion 25 at the natural return point.
Since it is located on the top and is insulated from the connection points 26 and 27 of the radio wave interference preventer 28, the control circuit of the electric sewing machine is reliably electrically open when the controller is not operated.

In this way, there is no need for any special mechanism or interlocking of switches for electrical safety during non-operation, and the simple structure eliminates the risk of unexpected accidents due to destruction of the radio interference preventer as described above. This is an idea that has great industrial and practical effects.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, FIG. 2 is a plan view showing a specific structural example of FIG. 1, and FIGS. 3 and 4 are conventional circuit diagrams. In the figure, 2 is a sewing machine controller, 21 is a resistor, 22
25 is an insulating part, 26 and 27 are first and second contacts, and 28 is a radio wave interference preventer.

Claims (1)

[Scope of utility model registration request] A variable resistance and contact switching contact is connected to one terminal of a pair of terminals connected to one end of each of the power source and the motor, and is operated in conjunction with an external step board, etc., and the contact is connected to one end of the motor when the motor is stopped. A first and a second contact are provided in the order of transition from to an operating state, a radio interference preventer is connected between the contacts, and a resistor for motor speed control is connected to the second contact, When the contact is at the natural return point, the motor is opened, and when the motor starts operating, the contact is connected to the first contact, and then the first and second contacts are short-circuited, and When the first contact is opened and the motor is energized through the resistor, and the motor is to stop, the first and second contacts are short-circuited from the state of contact with the resistor, and then the second contact is connected to the resistor. A sewing machine controller characterized in that the controller is configured to open a contact and further open a first contact.