JPH019018Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a device that electrically detects and displays the disconnection state of a heater used as a heat source in an injection molding machine or the like.

Conventionally, as a device for detecting and displaying a disconnection state of a heater, for example, an ammeter is connected directly to the power supply line of the heater, and this ammeter reads changes in the current flowing to detect a disconnection state of the heater. There are some known devices in which a current transformer is installed in the heater's power supply line to detect an electrical signal proportional to the energizing current, and based on this detection signal, a disconnection state of the heater is detected via an electronic circuit, etc. It is being

However, according to the above configuration, when the heater supply current becomes large, a current transformer must be installed, and the disconnection state is determined by reading the current value, which requires an analog determination.
The problem is that it takes time and effort to make a judgment, and it is easy to make an incorrect judgment. Further, according to the above-mentioned configuration, there are disadvantages in that the device is expensive and requires a plurality of circuit configurations.

Therefore, the inventor of the present invention has conducted various studies and prototypes in order to overcome all the problems of the conventional heater disconnection display device mentioned above, and to obtain a device that has a simple configuration and can be manufactured at low cost. By providing a circuit that detects the power supply status of the heater and a circuit that detects the energization status of the heater, and configuring the circuits to connect light-emitting indicators with different luminous colors to each circuit to display light emission, the power supply to the heater can be controlled. It was discovered that the disconnection state of the heater can be easily determined by the light emitting state of the light emitting indicator.

Therefore, the purpose of the present invention is to extract a signal indicating the power supply state to the heater and a signal indicating the energization state of the heater, display these signals by emitting light using a simple electric circuit, and determine the heater's power by the state of the emitted light color. It is an object of the present invention to provide a heater disconnection display device for an injection molding machine, etc., which can easily confirm a disconnection state.

In order to achieve the above object, in the present invention, a heater such as an injection molding machine is connected to a power supply circuit that passes through a power supply switch, and a voltage detection means such as a transformer and the energization state of the heater are connected to the power supply circuit. A current detector for detecting the voltage is connected and arranged, and light emitting diodes emitting light of different colors are connected to the output terminals of the voltage detecting means and the current detector, respectively, and a disconnection state of the heater is determined based on the light emitting state of these light emitting diodes. It is characterized by being configured as follows.

Next, embodiments of the heater disconnection indicating device according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a circuit diagram showing an embodiment of the device of the present invention. In FIG. 1, reference numeral 10 indicates a power switch, and contacts 10a,
10b is connected to the power supply circuit 14 of the heater 12. In addition, a power supply circuit 14 passing through a power switch 10
A voltage detection means such as a transformer 22 is connected to the power supply state detection circuit 16. Further, a current detector 18 for detecting the energization state of the heater 12 is connected to the power supply circuit 14 . A part of the power supply state detection circuit 16 and a current detector 18
The output terminals of each are connected to a light emitting display 20.
In this case, the light-emitting indicator 20 can be configured with a light-emitting element such as a light-emitting diode, for example, the light-emitting element A whose luminescent color is "red" is connected to the power supply state detection circuit 16, and the luminescent color is connected to the current detector. connects the "green" light emitting element B.

Next, the operation of the circuit configured as described above will be explained. Now, when the power supply switch 10 is closed, the heater 12 is in the power supply state, and if the heater 12 is normally energized, a predetermined electric signal is sent to the power supply state detection circuit 16 and the current detector 18. occurs. As a result, the light emitting indicator 20
In this case, light emitting elements A and B light up, and both light emitting elements A and B
Displays the composite color of each luminescent color (red and edge). Therefore, when the heater 12 becomes disconnected, the power supply state detection circuit 16 is normal, but the current detector 18
does not generate a detection signal. As a result, only the light-emitting element A (red) of the light-emitting indicator 20 is lit, and thereby the disconnection state of the heater 12 can be easily determined.

In the embodiment described above, the power supply status detection circuit 16 was constructed by connecting voltage detection means such as the transformer 22 to the power supply circuit 14 via the power supply switch 10.
For example, as shown in FIG.
It is also possible to use the cooperative contact 10c of the power switch 10 as the switching element 6.

Further, in the embodiments shown in FIGS. 1 and 2, a single-phase circuit is shown, but it goes without saying that the device of the present invention can be applied as is to a three-phase circuit.

As is clear from the embodiments described above, the device of the present invention is configured to detect the power supply state to the heater and the energization state of the heater, respectively, and light up light emitting indicators of different colors based on each detection signal. Therefore, it is possible to easily determine whether the heater is normal or broken by the difference in emitted light color, and it is possible to smoothly monitor and control various equipment equipped with heaters such as injection molding machines. can.

Furthermore, since the device of the present invention uses a current detector and a light emitting element that simply lights up in response to a detection signal as a display function, it not only has a simple circuit configuration but also significantly reduces manufacturing costs. Can be done. In addition, it is extremely easy to handle and has many practical advantages, such as not having to take into account current transformation phase issues, unlike when using a conventional current transformer.

Although the preferred embodiments of the present invention have been described above, it goes without saying that various design changes can be made without departing from the spirit of the present invention.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing one embodiment of a heater disconnection indicating device according to the present invention, and FIG. 2 is a circuit diagram showing another embodiment of the device according to the present invention. 10... Power switch, 12... Heater, 1
4...Power supply circuit, 16...Detection circuit, 18...Current detector, 20...Light-emitting indicator, 22...Transformer.

Claims (1)

[Scope of utility model registration request] A heater such as an injection molding machine is connected to a power supply circuit that passes through a power supply switch, and a voltage detection means such as a transformer and a current detector that detects the energization state of the heater are connected to the power supply circuit, and the An injection molding machine, etc., characterized in that light emitting diodes emitting light of different colors are connected to the output terminals of the voltage detecting means and the current detector, respectively, and a disconnection state of the heater is determined based on the light emitting state of these light emitting diodes. Heater disconnection indicator.