JPH044225Y2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field of the Invention The present invention relates to a digital panel meter with a simple configuration.

Prior Art and Problems A digital panel meter is attached to the panel of various devices to display voltage, current, etc. numerically, and has, for example, the circuit configuration shown in FIG. In the figure, IN is an input terminal, S1,
S2 is a switch circuit consisting of switching elements such as transistors, R is a resistor, SV is a reference voltage power supply,
C is a capacitor, ITG is an integrator, COM is a comparator, CNT is a control circuit, CTR is a counter,
CG is a clock oscillator and DSP is a display. The voltage Ex applied to the input terminal IN is integrated by the integrator ITG by turning on the switch circuit S1 for a fixed time Ts by the control circuit CNT, and after the fixed time Ts, the switch circuit S1 is turned off by the control circuit CNT. , switch circuit S2 is turned on,
The integrator ITG is connected to a reference voltage power supply SV, and integrates a reference voltage Es having a polarity opposite to that of the input voltage Ex, that is, toward zero voltage. When this integral output becomes zero, the output of the comparator COM becomes the control circuit.
CNT, and the control circuit CNT turns off the switch circuit S2. Integration time of input voltage Ex
If Ts is the integration time of the reference voltage Es until Tx and the integrated output become zero, then the relationship Ex=(Tx/Ts)Es holds, and the integration time Ts and the reference voltage Es are predetermined values. Therefore, the control circuit CNT uses a counter CTR to count the time from the time when the switch circuit S1 is turned off and the switch circuit S2 is turned on until the integral output becomes zero, that is, the integral time Tx, which is proportional to the input voltage Ex. A digital value is obtained and displayed on the DSP display. Such an operation is already known as a double integral method.

The conventional configuration of such a digital panel meter is to mount an integrator, counter, etc., which are integrated circuits on a printed circuit board, and house them in an outer box.A display is provided on the front side of the outer box. A front plate was provided on the front of the machine. The disadvantage is that the assembly requires screws, etc., and the assembly work is complicated.Also, the front panel on the front of the display reflects light from the outside, making it easy to recognize what is displayed on the display. There were cases where it was not easy to do so.

Purpose of the invention The object of the invention is to provide a digital panel meter that is easy to assemble, provides easy-to-read display content, and can be stably attached to various equipment panels. Examples will be described in detail below.

Embodiment of the invention Fig. 2 is a front view of an embodiment of the invention excluding the front plate, and Fig. 3 is a sectional view including the front plate.
is made of ABS resin, for example. The outer box 1 includes a top plate 2, a bottom plate 3, side plates 4 and 5, and a bottom plate 6.
The side plates 4 and 5 have a locking part 7 between the slits 8.
is formed, and is inserted into a mounting hole (not shown) in a panel of various devices, so that the locking part 7 is pushed into the outer box, then protrudes due to elasticity, and is fixed by the locking part 7. Further, guide grooves 9 are formed on the inner surfaces of the side plates 4 and 5, and a printed circuit board 20 is inserted into the guide grooves 9. A connecting portion 22 at one end of the printed circuit board 20 is projected from a long hole formed in the bottom plate 6 of the outer box 1, a connector 50 is inserted into the connecting portion 22, and a printed wiring between the contact spring 51 of the connector 50 and the connecting portion 22 is inserted. is contacted. Further, 52 indicates a contact pin that is brought into contact with the contact spring 51.

A vertical mounting plate 21 is fixed to the printed circuit board 20, and the wiring on the printed circuit board 20 and the wiring on the mounting plate 21 are connected. Also mounted on the printed circuit board 20 are circuit elements 23, 24, and 25 such as the integrator, comparator, and counter described with reference to FIG. The mounting plate 21 is dimensioned to be inserted between the upper plate 2 and lower plate 3 of the opening of the outer box 1, and the electrodes of the display 30 and the wiring of the mounting plate 21 are connected by soldering or the like. At the same time, the display 30 is fixed to the mounting plate 21.

The display 30 is composed of a light emitting diode, a gas discharge display tube, etc., and generally uses a segment type numeric display in the shape of a Japanese font. Furthermore, the second
In the figure, only two characters are shown, but the configuration is such that it is possible to display a desired number of digits.

By inserting the printed circuit board 20 on which the display 30 is fixed via the mounting plate 21 into the guide groove 9 of the outer box 1, the front surface of the display 30 becomes almost the same surface as the surface of the opening of the outer box 1. By fitting the front plate 40 to the outer case 1, the printed circuit board 20 including the display 30 is fixed within the outer case 1. That is, at the time of assembly, it is only necessary to simply insert and fit, and the assembly can be easily performed.

Figure 4 is a top view of the outer box, Figure 5 is a front view, and Figure 6 is a top view of the outer box.
The figure shows a sectional view, and the same reference numerals as in FIGS. 2 and 3 indicate the same parts. The reference numeral 10 in FIGS. 4 and 6 is a recess for locking the front plate 40, and the reference numeral 11 in FIG. 5 is an elongated hole formed in the bottom plate 6. This is for protruding the connecting portion 22. This outer box 1 has a locking portion 7
Since the outer box 1 has a slit 8 for forming the outer box 1, if a force is applied between the upper plate 2 and the lower plate 3, the outer box 1 will be deformed. However, by inserting the printed circuit board 20 into the outer box 1,
Since the mounting plate 21 is inserted between the upper plate 2 and the lower plate 3, deformation of the outer box 1 can be prevented. That is, when the outer box 1 is inserted into a mounting hole of a panel of various devices and fixed, deformation of the outer box 1 is prevented, and the fixed state can be maintained for a long period of time.

FIG. 7 is a front view of the front plate 40, FIG. 8 is a back view, and FIG. 9 is a sectional view. The front plate 40 is a colored transparent plate and is made of acrylic resin or the like. The surface of this front plate 40 has a rough so-called matte finish, and a diamond-cut surface 45 is formed except for the central portion 41 and the item display portions 42 on both sides thereof. The center part 41 corresponds to the front surface of the display 30, and the display contents of the display 30 are displayed through the center part 41.The item display part 42 is separated by a partition line 43, and for example, the unit of voltage is displayed. It is used to display V, mV, DC, etc. indicating direct current on printed materials, etc. Also, front plate 40
A protrusion 46 is formed on the inner surface of the frame portion 44 of the outer box 1.
When fitted, the protrusion 4 fits into the recess 10 of the outer box 1.
6 enters, and the front plate 40 is fixed to the outer box 1.

Fig. 10 is a partially enlarged view of the front plate 40, and Fig. 11 is a cross-sectional view thereof. In comparison, by using a diamond-cut surface, light from the outside is less likely to be reflected and enter the eyes, and only the light-emitting display content of the display 30 is led out from the center portion 41 and leaks outside the center portion 41. This prevents the contrast from decreasing. Conventionally, the diamond cut surface 45
Previously, a paper pattern was provided between the display and the front plate for the portion corresponding to the above, but according to the present invention, it is no longer necessary to provide such a paper pattern.

Effects of the invention As explained above, the present invention has two side plates 4 and 5.
An outer box 1 having a guide groove 9 formed on the inner surface thereof, a locking part 7 for fixing to the panel between the slits 8, a long hole 11 formed in the bottom plate 6, and a recess 10 formed on the outside of the opening. , a printed circuit board 20 on which a circuit element is mounted and has a connecting part 22 at one end, and an upper plate 2 and a lower plate 3 fixed to the printed circuit board 20 in the vertical direction and at the open opening of the outer box 1. A mounting plate 21 of a size that can be inserted, a display 30 fixed to the mounting plate 21, and the printed circuit board 20 are inserted into the guide groove 9, and the connecting portion 22 of the printed circuit board 20 is connected to the length of the bottom plate 6. It has a front plate 40 that protrudes from the hole 11 and covers the front surface of the display 30. The front plate 40 has a diamond-cut surface 45 around a central portion 41 facing the display 30, and It has a protrusion 46 for engaging and fixing in the recess 10 of the box, and by forming the diamond cut surface 45 on the front plate 40, the displayed contents of the display 30 are made very easy to see as described above. The front plate 40 allows the printed circuit board 20 to which the display device 30 is fixed via the mounting plate 21 to be fixed inside the outer box 1, and assembly can be performed without using screws or the like. Furthermore, since the upper plate 2 and lower plate 3 of the open opening portion of the outer box 1 are supported from inside by the mounting plate 21, even if the slits 8 are formed in the side plates 4 and 5, the outer box 1 is No longer deformed,
When attached to a panel, it will be securely and stably fixed. Note that the diamond cut surface 45 can be formed not only by parallel grooves as in the embodiment but also by grooves in any direction.
It is also possible to easily shield the circuit elements on the printed circuit board 20 from external electromagnetic fields by inserting a shielding plate inside one or both of the lower plate 3 and the lower plate 3.

[Brief explanation of drawings]

Fig. 1 is a block diagram of the main parts of a digital panel meter, Fig. 2 is a front view of the embodiment of the present invention with the front plate removed, Fig. 3 is a sectional view including the front plate of the embodiment of the present invention, and Fig. 4 The figure is a top view of the outer box, Fig. 5 is a front view of the outer box, Fig. 6 is a side view of the outer box, Fig. 7 is a front view of the front plate, Fig. 8 is a back view of the front plate, and Fig. 9 is a front view of the outer box. The figure is a sectional view of the front plate, Figure 10 is a partially enlarged view of the front plate,
FIG. 11 is a partially enlarged sectional view of the front plate. 1 is an outer box, 2 is an upper plate, 3 is a lower plate, 4 and 5 are side plates, 6 is a bottom plate, 7 is a locking part, 8 is a slit, 9 is a guide groove, 10 is a recessed part, 11 is a long hole, 20 is a printed circuit board, 21 is a mounting plate, 22 is a connection part, 23, 2
4 and 25 are circuit elements, 30 is a display, 40 is a front plate, 41 is a center portion, 42 is an item display portion, 43 is a partition line, 44 is a frame portion, 45 is a diamond cut surface, 46
is a projection, 50 is a connector, 51 is a contact spring, 52
is the connection bin.

Claims (1)

[Scope of utility model registration request] Consisting of an upper plate, a lower plate, both side plates, and a bottom plate, guide grooves are formed on the inner surfaces of the both side plates, and a locking part for fixing to the panel is formed between the slits, and a long hole is formed in the bottom plate. and an outer box having a recess formed on the outside of the opening, a printed circuit board on which a circuit element is mounted and having a connection part for connecting to a connector at one end, and an outer box fixed vertically to the printed circuit board. a mounting plate of a size that can be inserted between the upper plate and the lower plate of the open opening portion; a display fixed to the mounting plate;
The printed circuit board is inserted into the guide groove so that the connecting portion of the printed circuit board protrudes from the elongated hole of the bottom plate, and the outer panel is inserted so as to prevent the printed circuit board from escaping together with the display fixed to the mounting plate. and a front plate fitted into the open opening of the box, the front plate having a diamond-cut surface around the central part facing the display, and a diamond-cut surface for engaging and fixing in the recess of the outer box. A digital panel meter characterized by having a protrusion.