JPH0425774A - Inspecting device for sliding resistor - Google Patents

Abstract

PURPOSE:To enable an inspection for defective slide contact easily for everyone by comparing electric potentials at the connecting point of 1st, 2nd resistors and at the slide terminal of a sliding resistor, holding the comparison results, and displaying them. CONSTITUTION:To a fixed terminal 4 of the sliding resistor 1 to be inspected, the 1st, 2nd resistors 13, 14 connected in series are connected, and also a 3rd resistor 15 is connected to the slide terminal 5. Then, the potentials at the connecting point of resistors 13, 14 and at the terminal 5 are compared in a comparator circuit 16, and the output signals are held by a self-holding circuit 17 then displayed by a display circuits 19, 20. Thus, an accurate and cost-saving inspection with high workability, in which high skillfulness and concentrating ability are not requested, is performed in the work for deciding normal/defective articles.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a sliding resistor testing device for testing sliding contact failure of a sliding resistor.

[Conventional technology]

FIG. 2 is a block diagram showing a conventional sliding resistor testing device. In the figure, 1 is a sliding resistor to be tested, and 2 is its slider. 3 and 4 are fixed terminals of this sliding resistor 1, and 5 is its sliding terminal. 6 is a positive power supply terminal to which one of the fixed terminals of the sliding resistor 1, for example, the fixed terminal 3, is connected, and 7 is a negative power supply to which a power supply device (not shown) is connected between this positive power supply terminal 6. It is a terminal. Reference numeral 8 denotes a fixed resistor connected between this negative power supply terminal 7 and the other fixed terminal of the sliding resistor 1, for example, the fixed terminal 4. 9 is a synchroscope for observing the current flowing from the slider 2 of the sliding resistor 1 to the negative power supply terminal 7, and 10 is its display screen.

Next, the operation will be explained. When a power supply device is connected between the positive power supply terminal 6 and the negative power supply terminal 7 and a predetermined voltage is applied, a current of 1. flows from the slider 2 of the sliding resistor 1 to the synchroscope 9. is divided. The synchroscope 9 displays the change in the value of the current I on the display screen 10. Here, FIG. 3 is an explanatory diagram showing a display example of the display screen 10 of the synchroscope 9. In the figure, 11 is a display waveform showing a change in the current 2, and 12 is a display waveform 11 due to a sliding contact failure. Each shows the disturbance.

That is, as the slider 2 of the sliding resistor 1 is gradually moved from the fixed terminal 3 toward the fixed terminal 4, the current 12 shunted by the slider 2 decreases smoothly. Therefore, the displayed waveform 11 on the display screen 10 of the synchroscope 9 decreases as the resistance value changes as the slider 2 moves, as shown by the solid line. Here, if a contact failure occurs while the slider 2 is moving, the current I2 shunted by the slider 2 is instantaneously interrupted. Therefore, the displayed waveform 11 on the display screen 10 of the synchroscope 9 undergoes sudden fluctuations due to poor sliding contact of the slider 2, and waveform disturbances 12 as shown by broken lines occur instantaneously.

When the operator observes the displayed waveform 11 displayed on the display screen 10 of the synchroscope 9 and confirms the disturbance 12 in the waveform, the operator determines that the sliding resistor 1 is defective.

[Problem to be solved by the invention]

Since the conventional sliding resistor testing device is configured as described above, the waveform disturbance 12 displayed on the display screen 10 of the synchroscope 9 is instantaneous, and the occurrence of the waveform disturbance 12 can be prevented. It is necessary to monitor and determine whether the sliding resistor 1 is a good product or a defective product, and this determination work requires a high level of skill and extremely high concentration. There was a problem.

This invention was made in order to solve the above-mentioned problems, and does not require a high degree of skill and concentration to judge whether a good product or a defective product. The object of the present invention is to provide a sliding resistor testing device that can test for sliding contact defects.

Means for Solving Problem C] The sliding resistor testing device according to the present invention includes a first resistor and a third resistor connected in series to one of the fixed terminals of the sliding resistor to be tested. A comparator circuit that connects a third resistor to a sliding terminal and compares the potential between the connection point of the first and second resistors and the sliding terminal of the sliding resistor. It is equipped with a self-holding circuit that holds the output signal of the circuit, and a display that displays the output signal of the self-holding circuit.

[For production]

The sliding resistor testing device according to the present invention uses a comparison circuit to detect a potential at a connection point between a first resistor and a second resistor connected to one of the fixed terminals of the sliding resistor to be tested; By comparing the potential with the sliding terminal of the sliding resistor to which the third resistor is connected, and holding the comparison result in a self-holding circuit and displaying it on the display, it is possible to determine whether the product is good or defective. To realize a sliding resistor inspection device that does not require a high degree of skill and concentration.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, 1 is a sliding resistor, 2 is a slider, 3 and 4 are fixed terminals, 5 is a sliding terminal, 6 is a positive power terminal, and 7 is a negative power terminal. The detailed explanation will be omitted since it is the same as or corresponds to the conventional parts mentioned above.

Moreover, I3 and 14 are connected in series with each other, and are connected between one of the fixed terminals of the sliding resistor I, for example, the fixed terminal 4, and the negative power supply terminal 7. This is a fixed resistor as the second resistor. Reference numeral 15 denotes a fixed resistor as a third resistor connected between the sliding terminal 5 of the sliding resistor 1 and the negative power supply terminal 7.

Reference numeral 16 indicates a comparison circuit using a differential amplifier or the like, which compares the potential at the connection point of the fixed resistors 13 and 14 connected in series with the potential at the sliding terminal 5 of the sliding resistor 1, and 17 indicates a comparison circuit. 16 is a self-holding circuit such as a flip-flop that holds the output signal; 18 is a reset switch for resetting this self-holding circuit 17; 19 is a light emitting diode as an indicator that lights up while the sliding resistor 1 is in good condition according to the output signal of the self-holding circuit 17; 20 is a light emitting diode that lights up the sliding resistor 1 according to the output signal of the self-holding circuit F; This is a light emitting diode as an indicator that lights up when a defect is detected.

Next, the operation will be explained. When a power supply device is connected between the positive power supply terminal 6 and the negative power supply terminal 7 and a predetermined voltage is applied, the sliding resistor 1 to the fixed resistor 13 are connected as in the conventional case.
．． 14 to the current 1. flows, and a current I2 is shunted from the slider 2 of the sliding resistor 1 to the fixed resistor 15. The comparison circuit 16 compares the voltage drop across the fixed resistor 15 due to this current (2), that is, the potential a of the sliding terminal 5 of the sliding resistor 1, and the current I
The voltage drop across the fixed resistor 14, that is, the potential at the connection point between the fixed resistors 13 and 14 is compared.

As a result, the comparison circuit 16 maintains its output signal C at a predetermined polarity unless the potential a becomes 0 volts, and inverts the output signal C when the potential a becomes O volts. That is, if the sliding resistor 1 to be inspected is a good product and no sliding contact failure occurs even when the slider 2 is moved, the current I2 will always flow normally, so the potential a will never reach O volts. do not have. However, when a sliding contact failure occurs, the current I2 is momentarily cut off, and the potential a becomes 0 port during that time. Therefore, when a sliding contact failure occurs in the sliding resistor 1, the comparison circuit 16
The output signal C is instantaneously inverted.

Here, when the reset switch 18 is closed, the self-holding circuit 17 transitions to a reset state, and sets the output signal e to a high level and the output signal f to a low level. In such a reset state, when the output signal C of the comparator circuit 16 is inverted, the self-holding circuit 17 transitions to a set state, the output signal e becomes low level, the output signal f becomes high level, and this state is maintained thereafter. Therefore, if a sliding contact failure does not occur in the sliding resistor 1, the self-holding circuit 17 maintains the reset state and sets the output signal f to a low level, and if a sliding contact failure occurs midway through, the self-holding circuit 17 returns to the set state. Changes and output signal e
is set to low level.

The light emitting diode 19 emits light when the output signal f becomes low level to indicate the normality of the sliding resistor l, and the light emitting diode 20 emits light when the output signal e becomes low level.
It is displayed that a sliding contact failure has occurred in the sliding resistor 1. Due to the action of the self-holding circuit 17, the light emitting diode 20 continues to emit light even after the sliding contact failure of the sliding resistor 1 is resolved.

The operator observes the light emission from the light emitting diodes 19 and 20, and if the light emitting diode 19 emits light until the slider 2 moves from the fixed terminal 3 to the fixed terminal 4, the operator determines that the sliding resistor 1 is a good product. , if the light emitting diode 20 emits light in the middle, it is determined to be a defective product.

If a defective product is detected, the reset switch 18 is closed and the self-holding circuit 17 is activated before inspecting the next sliding resistor 1.
Reset.

In the above embodiment, fixed resistors were used as the first to third resistors, but variable resistors may also be used, and by adjusting the combination of their resistance values. , it is possible to obtain a sliding resistance value testing device capable of testing sliding resistors of any resistance value.

Further, in the above embodiments, a light emitting diode was used as the indicator, but other visible display means such as a lamp or even an audible display means such as a buzzer may be used. It has the same effect as the example.

〔Effect of the invention〕

As described above, according to the present invention, the potentials between the connection point of the first and second resistors and the sliding terminal of the sliding resistor are compared, and the comparison result is held and displayed on the display. Because of this structure, the work of determining good/defective products does not require a high level of skill or concentration, and does not require expensive equipment such as a synchroscope, making the work easier. This has the advantage of providing a highly accurate and inexpensive sliding resistor testing device.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a sliding resistor testing device according to an embodiment of the present invention, FIG. 2 is a block diagram showing a conventional sliding resistor testing device, and FIG. 3 is a block diagram showing the display screen of the synchroscope. It is an explanatory diagram showing a display example. 1 is a sliding resistor, 2 is a slider, 3 and 4 are fixed terminals, 5 is a sliding terminal, 13 is a first resistor (fixed resistor), 14 is a second resistor (fixed resistor) ), 15 is the third resistor (fixed resistor), 16 is the comparator circuit, 17 is the self-holding circuit, 19゜20 is the indicator (light emitting diode) In addition, in the diagram, the same reference numerals refer to the same or equivalent parts. show.

Claims (1)

[Claims] A first resistor and a second resistor are connected in series with each other and are connected to one of the fixed terminals of the sliding resistor to be tested, and a second resistor is connected to the sliding terminal of the sliding resistor. Third
a resistor, a comparison circuit that compares a potential at a connection point of the first resistor and the second resistor with a potential at a sliding terminal of the sliding resistor, and holds an output signal of the comparison circuit. 1. A sliding resistor testing device comprising: a self-holding circuit; and a display displaying an output signal of the self-holding circuit.