JPS58124480A - Danger preventing apparatus of sewing machine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hazard prevention device for an electric sewing machine, and more particularly to a device for preventing hazards caused by malfunctions caused by a drop in power supply voltage of a control circuit thereof.

As shown in FIG. 1 as a general configuration example, a single-motion sewing machine includes a motor 10, a sewing machine main body 24, a control device 32, and the like. The rotational output of the motor io is transmitted to the sewing machine body 24 via the clutch friction plate 12, clutch plate 16, f-918, "i HERU) 28 O! Himi-77f-IJ26. The clutch plate 16 is the clutch friction plate 12 and the brake friction plate 14, and is movable therebetween in the axial direction of the motor 1G.The clutch plate 16 is positioned between the clutch coil 20 and the brake friction plate 14.
When excited, it contacts the clutch friction plate 12 and the motor l
The rotation of O is transmitted to l-reel 18, and
To excite 2 and 1. Contact with brake friction plate 14! −
It is possible to suddenly stop the simultaneous rotation of the reel 18. In front, on the side of the sewing machine body 24, there is a needle position and speed detector 30. Thread trimming coil 1 that drives the thread trimming mechanism
M etc. are provided.

On the other hand, the control device 92 includes, for example, -e/ for operating the sewing machine.
34 are connected via a connecting rod 36.

The connection between the sewing machine body 24 and the control device 320 is @4G.

They are electrically connected to each other by 42, 44, 46, 52, etc.

FIG. 2 shows an example of the configuration of the control device 32. As shown in FIG. In the figure, the control device 32 includes a control circuit 48 and a control power supply voltage detection circuit SO. The control circuit 48, for example,
/? of the output section based on the operation status of 4. Conducts conduction control of the power transistor Tl.

This Tsuyaward 2 Inzostar τ1 is interposed in series between the /4 power supply v2 and the clutch coil 200 to control the current supplied to the Tsuyaward clutch coil 20. The control power supply voltage detection circuit 5G is configured to generate a detection output and drive the control transistor T2 into conduction when the power supply voltage v1 of the control circuit 48 is below a specified value. This control transistor T
2 is driven into conduction, the tower transistor Tl
The pace current, that is, the drive current, is clamped, so that the output/4W transistor TI is forcibly made non-conductive. As a result, for example, when the power is turned on or off, the power supply voltage v of the control circuit 48 is
1 falls below a specified value necessary for the normal operation of the control circuit 48, the Δ word transition state 1 of the output section is forcibly made non-conductive to invalidate the output of the control circuit 48, and this Please do your best to prevent the risk of malfunction of your electric sewing machine.

However, in the conventional electric sewing machine safety device configured as described above, a control transistor is required for clamping the pace current of each power transistor in the output section provided for each function. For this reason, each time the functionality increases, the number of required parts increases, and a large space is also required to house the parts, which further increases costs and complicates the configuration.

This invention was made in view of the above-mentioned conventional problems, and its purpose is to prevent dangers caused by malfunctions of electric motors that have multiple output points in the control circuit. To provide a danger prevention device for an electric sewing machine which can be configured easily and at low cost with a small number of parts by using a control element.

In order to achieve the above object, the present invention provides a function for driving a working sewing machine by a motor, a function for stopping the sewing machine by a braking mechanism, and a function for controlling each of these functions individually through an output section using an arm transistor. In the electric sewing machine, the electric sewing machine is configured such that a power source for the drive unit that supplies the pace current of the arm transistor is supplied from a common power source that is separate from the cough/arm transistor O power source, and the control circuit When the power supply voltage is below a specified value, only the common power supply of the drive section is cut off and the power transistor of the output section is forcibly rendered non-conductive, thereby disabling the output of the control circuit. It is characterized by being configured as follows.

Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

FIG. 3 shows an embodiment of the machine safety device according to the present invention. Here, the main body of the sewing machine is constructed in the same manner as the conventional example described above, and therefore a description thereof will be omitted. Shown in sWA is a control device 32, which is connected to a control circuit 48.
, a control power supply voltage detection circuit 5, and a danger prevention device 54. The control circuit 4 outputs a clutch signal output 48, a brake signal output 48B, and a thread trimming signal output 4110, respectively. Each of the signal outputs 48, 48B, and 480 respectively provides a pace current to the /4 power transistors TI, Tz, and T4 of the output section through the driver transistors T5, 7, and 7, respectively. Each power transistor 'r1173, T4 connects to the clutch coil 20. Coil during play "" % AfJ C coil 2M and Δwar power supply v
conduction control between 2 and 2.

ζζ, a driver transistor T5, which supplies the pace current of each Δ word transistor T1, T3, T4, respectively;
T6 and T7 are operated by a common power supply v3 different from the upper E/+9-power @'12. This common power supply v3 is supplied via the danger prevention device 54. Furthermore, this safety device 54 operates based on the detection output of the control power supply voltage detection circuit 50, and if the power supply voltage v1 of the control circuit 48 is lower than the specified value necessary for normal control operation. , the transistor T9 is in the on state, and as a result, the control transistor TIO inserted in series with the common power source v3 is in the off state and the supply of the common power source v3 is stopped. As a result, the nine-power transistor T of each output section
1, T3, and T4 are all forcibly rendered nonconductive by cutting off their pace current supply sources. As a result, the collapse of the output section of the control circuit 48 is also invalidated, and even if the control circuit 48 has malfunctioned due to a decrease in the control power supply voltage Vl, its recreational operation status is not output. Therefore, danger due to malfunction of the electric sewing machine is prevented. Here, the control power supply voltage detection circuit 50 includes a resistor R, for example, as shown in FIG.
1% R2, Zener diode ZD, diode D, capacitor O, transistor T8, etc. In this case, when the electric sewing machine is turned on, the control power supply voltage v1 rises and the capacitor C is connected to the resistor R.
1 and is charged. Until the potential of the capacitor C reaches the potential determined by the Zener diode ZD, the transistor T8 is in an off state.

Next, when the potential of the capacitor C exceeds the potential determined by the Zener diode ZD, the transistor T8 is turned on because a pace current flows through the Zener diode ZD. In this state, the danger prevention device s4
The H control transistor TIO becomes conductive and supplies the common power supply v3 to each of the driver transistors T5, 'r6, and T7, and the output operation of the control circuit 48 is performed normally.

Now, what should be noted here is that the above-mentioned risk-prevention rounding control element only requires one transistor TIG for multiple output sections, which makes it simple and easy to use with a small number of components. It is designed so that the danger prevention device can be constructed at low cost. Further, even if the number of output parts is further increased to nine, there is no need to add the above-mentioned danger prevention device 54. Therefore, in the above-mentioned embodiment, an example was shown in which the risk of malfunction of the clutch coil, brake coil, and thread trimming coil is prevented. Prevention of danger due to malfunction can be easily added.

In the above embodiment, driver transistors T5, T
Although the common power supply v3 of T7 is controlled, the driver transistor T5. A similar effect can be obtained by controlling the input side of T6 and T70, that is, the power supply of the control circuit 48, by the control transistor 'r10 of the #1 prevention device 54.

As described above, the danger prevention device for an electric sewing machine according to the present invention requires only one control element even if there are a large number of danger prevention functions, and as a result, the number of parts is reduced. It can be configured easily and at low cost.

[Brief explanation of drawings]

Figure 1 is a block diagram showing an example of the configuration of a conventional electric sewing machine.
Figure 2 shows the control device part! Lock circuit diagram, 3rd
The figure is a circuit diagram showing one embodiment of the danger prevention device for an electric sewing machine according to the present invention.1 The same members in the figure are denoted by the same reference numerals, 10 is the motor, 2G is the clutch coil, 22 is the brake coil, and 24 is the same reference numeral. ξ Thin main body, 32 is a control device, 48
is a control circuit, 50 is a control power supply voltage detection circuit, 54L is a danger prevention device, T1%'ra and 'r4 are respective output transistors, vl is a control power supply voltage, v2 is a quantity power supply, and V3 is a drive TM is a thread cutting coil, T10 is a control transistor, and T5, T6, and T7 are driver transistors of the drive section. Agent Patent attorney Shin Kuzuno - (1 other person) Figure 1 Figure 2'' Figure 3 32 Commissioner of the Japan Patent Office 1, 'IG (display of 'I-') Patent Application Sho b7
-007235 No. 2, Title of invention: Electric sewing machine /
I2 Risk Protection 1lKi#3, Amendment -6h Relationship with tenant farming Patent applicant: Tojo; [Tocho-dai IN-ku Marunouchi-°-
j'th No. 2 and 3 Name (601) Mitsubishi Electric Co., Ltd. Representative R piece 111 Jin 8 part 4, agent address Tokyo H (III-ku Maru 0-J'11)
2 No. 3 No. 5, Supplement 11 λ4 Elephant

Claims (1)

[Scope of Claims] In the sewing machine, the power source of the drive unit that supplies the pace current of the /9 watt transistor is configured to be supplied from a common power source different from the power source of the 9 watt transistor, and the power supply voltage of the control circuit is below a specified value. In the case of , only the common power supply of the drive section is cut off, the /4 power transistor of the output section is forcibly made non-conductive, and the output of the control circuit is thereby disabled. A safety device for electric sewing machines featuring: (2) A danger prevention device for an electric sewing machine, characterized in that in the device according to claim (1), the functions controlled by the control circuit include an automatic thread trimming function or a thread removal function. .