JP3069780U - Electric measuring instrument - Google Patents

Abstract

(57) [Summary] [PROBLEMS] The present invention realizes an electric measuring instrument that is easy to handle and easy to measure, as well as preventing erroneous operation of high current measurement using test leads. The present invention relates to an electric measuring instrument for measuring a quantity of electricity or the like of a circuit to be measured by replacing a plug of a test lead connected to a connection hole of a connection terminal corresponding to a measurement range provided on a panel of an instrument main body. , An electric measuring instrument provided with a safety mechanism for automatically opening and closing a connection hole of a connection terminal for a high range provided in the instrument body. In addition, a safety cover is provided for the safety mechanism, and an electric measuring instrument that automatically opens and closes the connection hole with the safety cover is configured. In addition, an electric measuring instrument in which the safety cover was displayed in red was configured. Furthermore, an electric measuring instrument was constructed in which the display area for the high range in the measurement range was displayed in a primary color different from the panel color and red.

Description

[Detailed description of the invention]

[0001]

[Technical field to which the invention belongs]

 The present invention relates to an electric measuring instrument, and more particularly to an electric measuring instrument for measuring a current or the like corresponding to a measurement range by connecting a test lead plug to a connection terminal of a main body of the electric measuring instrument.

[0002]

[Prior art]

 FIGS. 6A and 6B are explanatory diagrams showing the configuration of a conventional digital multimeter of this kind. FIG. 6A is a front view of the main body of the digital multimeter, and FIG. 6B is an enlarged side view of the safety cap. In FIG. 6A, 101 is a meter main body, 102 is a liquid crystal display, 103 is a power switch, 104 is three push button switches, and 105 is a dial type switch. 106 to 109 are four connection terminals for measurement having the same shape, 106 is a connection terminal (voltage terminal) for voltage and frequency, 107 is a common connection terminal, 108 and 109 are low current and high current. Connection terminal.

In FIG. 6B, reference numeral 110 denotes a safety cap made of light blue resin. As shown in the figure, the safety cap 110 has a disk-shaped head 111 and a column-shaped leg 112 formed with a slot. The leg portion 112 formed with a slot can be detachably inserted into any of the voltage terminals 106 and the like, and the head portion 111 covers the surface to close the connection hole. The safety cap 110 is always inserted into the connection terminal 109 for high current. In addition, a set of test leads indicated in red and black is provided as an accessory (see Fig. 3).

In the conventional digital multimeter shown in FIG. 6, when measuring a low DC current of, for example, about 200 μA to 200 mA, the changeover switch 105 is turned to match the corresponding measurement range. A digital multimeter is connected in series with the circuit under test by using a test lead having a black plug connected to the common terminal 107 and a test lead having a red plug connected to the low current connection terminal 106. Then, the DC current flowing through the circuit under test is measured. When measuring a high current of 20 A or less, for example, the safety cap 110 is removed and the red plug is replaced with the connection terminal 109 for high current.

A current between two points can be measured in the same manner as described above using a test lead in which the red plug is replaced with the connection terminal 109 and a test lead in which the black plug is fixed to the common terminal. ing. In this case, the safety cap 110 removed from the high-current connection terminal 109 is transferred to the adjacent low-current connection terminal 108 or voltage terminal 106. It is described in the instruction manual that after the high current measurement, the safety cap 110 is returned to the original 20 A measurement terminal, and the connection hole of the high current measurement terminal 109 is always covered and closed.

Generally, the input circuit of this type of high-current connection terminal 109 does not have a protection circuit such as a fuse, and is connected to the common terminal 107 at approximately 0.01Ω. Therefore, if a high voltage is directly applied between these two connection terminals 107 and 109 by mistake, a short circuit occurs and a high current flows to the test leads. For this reason, the test leads generate heat due to the high current that flows, which may cause a burn accident for the measurer. In order to avoid the danger due to such an erroneous operation, a warning is given that the measurement of the connection terminal 109 of 20A is used only for a circuit through a circuit breaker or the like of 20A or less.

[0007]

[Problems to be solved by the invention]

 The conventional digital multimeter shown in FIG. 6 is provided with the safety cap 110 that can be attached to and detached from the plurality of connection terminals 106 as described above. Then, the safety cap 110 is always inserted into the connection terminal 109 of 20A to prevent the risk of erroneous operation of the measurement using the test leads. However, the safety cap 110 has to be replaced before and after the measurement of 20A, which has the disadvantage that the measurement operation is complicated. If the troublesome double replacement operation is neglected, the safety cap 110 may be lost. If the connection terminal 109 is left open while it is lost, there is a problem that the above-described accident may occur.

The present invention has been made in order to solve the above-mentioned conventional problems. The present invention not only prevents erroneous operation of high current measurement using test leads, but also makes measurement operation simple and easy. Is intended to realize a convenient electric measuring instrument.

[0009]

[Means for Solving the Problems]

 The present invention relates to an electric measuring instrument for measuring the electric quantity, etc. of a circuit to be measured by replacing a plug of a test lead connected to a connection hole of a connection terminal corresponding to a measuring range provided on a panel of an instrument main body. This is an electric measuring instrument equipped with a safety mechanism that automatically opens and closes the connection hole of the high-range connection terminal provided on the instrument body. Further, in the above means 1, a safety cover is provided in the safety mechanism, and an electric measuring instrument is configured to automatically open and close the connection hole by the safety cover. Further, in the above means 2, an electric measuring instrument in which the safety cover is displayed in red is configured. Further, in the above-mentioned means 3, an electric measuring instrument in which a display area for a high range in the measurement range is displayed in a primary color different from the panel color and red.

[0010]

[Embodiment of the invention]

 Hereinafter, embodiments of the present invention will be described with reference to the drawings. Embodiment 1 FIG. FIG. 1 is a front view showing the structure of the first embodiment of the present invention, FIG. 2 is a left side view of FIG. 1, and FIG. 3 is an explanatory diagram showing the structure of the test leads. Are shown. 1 to 3, reference numeral 1 denotes a main body of the digital multimeter according to the first embodiment, and reference numeral 2 denotes a panel on the surface of the main body 1. The main body 1 is molded of a black-gray hard resin, and is composed of two parts, an upper case and a lower case on the panel 2 side.

Reference numeral 3 denotes a liquid crystal display provided on the upper portion of the panel 2, 4 denotes a shift switch for switching between AC / DC and the like, and 5 and 6 denote hold switches for data and range. Reference numeral 7 denotes a function switch that also functions as a power switch. Around the function switch 7, a measurement object and a measurement range corresponding to switching of power supply ON / OFF, voltage V, and the like are displayed. In particular, the area of the 20 A range following the low current range of about μA and mA is colored in yellow (hatched in FIG. 1), which is a primary color different from the color of the other panel surface, and in this yellow background. "20A" indicating the range of the high current is displayed in the red square frame.

When the function switch 7 is rotated by the knob 71, the measurement target and the measurement range displayed in the peripheral portion such as power ON / OFF, V... Are sequentially and intermittently switched. 8 is a connection terminal (common terminal) such as a negative common terminal, 9 is a connection terminal for low current measurement (low current terminal), and 10 indicated by a dotted line is a connection terminal for high current measurement (high current terminal). . Reference numerals 11 and 12 denote a pair of test leads of the same shape and red and black, 13 denotes a plug of test leads 11 and 12, 14 denotes a lead wire, 15 denotes a grip, 16 denotes a flange, and 17 denotes a tip test. It is a pin.

The plug 13 is formed in a cylindrical shape, is inserted into each connection terminal such as the above-mentioned common terminal 8 and is detachably connected to the main body 1. As shown in FIG. 2, these test leads 11 and 12 are held in two holding grooves 19 formed on the side surface of a meter cover 18 made of a soft resin surrounding the five surfaces of the main body 1 when not in use. I have. Reference numeral 20 denotes a safety cover that performs a function corresponding to the conventional safety cap 110. The safety cover 20 is formed of a red resin, and exposes a substantially Y-shaped portion including a base 21 and a sector 22 on the panel 2. FIGS. 4 and 5 show the configuration of the main part where the safety cover 20 is provided.

FIG. 4 is a longitudinal sectional view of a main part of the first embodiment, and FIG. 5 is a perspective view of the main part of the first embodiment as viewed from the inner surface. 4 and 5, reference numeral 23 denotes a shaft portion protruding below the base 21 of the safety cover 20, reference numeral 24 denotes a swinging cylinder into which the shaft portion 23 is fitted, and reference numeral 25 denotes a screw. The screw 25 fixes the shaft portion 23 and the swing cylinder 24. 26 is a spring arm integral with the swinging cylinder 24, 27 is a coil spring having one end suspended from a standing piece 28 of the spring arm 26, and 29 is a mounting hole provided in the upper housing. The swing cylinder 24 is inserted together with the safety cover 20 so as to be swingable about the mounting hole 29. These components such as the safety cover 20 constitute a safety mechanism S.

Reference numeral 31 denotes a panel plate provided on the surface of the upper housing, and 32 denotes a main printed circuit board. 5 is a standing piece provided on the inner surface of the upper housing, 34 is a dial frame of the function switch 7, 35 is an enclosing cylinder for fixing the upper and lower housings, and 36 is a low current terminal. Reference numeral 9 denotes an envelope surrounding the high-current terminal 10, and 37 denotes a screw stud for fixing a small printed board for the connection terminal. The other end of the coil spring 27 is locked to the upright piece 33, and gives a swing rotation to the swing cylinder 24 by a contraction force. The spring arm 26 abuts on the surrounding cylinder 35 due to the contraction force, so that the safety cover 20 always closes the high current terminal 10.

Also in the case of the first embodiment of the present invention having the above-described configuration, each plug 13 of a pair of test leads 11 and 12 of red and black is connected to predetermined connection terminals 8 and Measurement of voltage, current, etc. is performed by connecting to any one of 9 and 10. In the first embodiment of the present invention, the operation of measuring a high current is different from the conventional one. For example, when measuring the 20 A range following the low current measurement in the first embodiment, first, the knob 71 is turned and the dial is turned to switch the function switch 7 to the 20 A measurement range. Next, the user presses the shift switch 4 and selects either AC or DC while viewing the display symbols that can be switched one after another on the liquid crystal display 3.

Next, the red plug 13 is pulled out from the low current terminal 9, a finger is placed on the sector 22 of the red safety cover 20 exposed on the panel 2, and the clockwise rotation is performed against the contraction force of the coil spring 27. (The reverse direction in FIG. 5 of the inner view). The clockwise rotation of the sector 22 causes the coil spring 27 to be elongated, the upper surface of the low current terminal 9 is closed, and the high current terminal 10 is opened. That is, the sector 22 rotates in the direction of the solid arrow from the position indicated by the two-dot chain line in FIG. Here, the plug 13 pulled out from the low current terminal 9 is inserted into the opened high current terminal 10, and the preparation for measurement in the high current range is completed.

Thereafter, when the measurement of the high current range in accordance with the above-mentioned handling rules is completed, and the plug 13 of the test lead 12 is pulled out, the sector 22 rotates together with the swinging cylinder 24 in a substantially counterclockwise direction by about 90 degrees. Then, the low current terminal 9 is opened and restored to the original position, and the high current terminal 10 returns to the normal state again and is automatically closed. As described above, in the first embodiment of the present invention, the preparation for high current measurement is performed by operating the red safety cover 20 provided on the range area displayed in yellow. Therefore, the operator operates the safety cover 20 of the same color while viewing the red “20A” displayed on the yellow background of the primary color, so that the operator can be alerted to the handling in the active manner based on the use of these identifiable colors. Will be evoked. As a result, the measurement operation of the high current by the measurer is visually cautious, and it is possible to avoid the occurrence of the above-mentioned danger caused by an erroneous operation.

When the measurement of the high current is completed as described above and the plug 13 of the test lead 12 is pulled out from the high current terminal 10, the sector 22 simultaneously swings and the high current terminal 10 is automatically closed. Is done. The safety cover 20 is fixed to the swing cylinder 24 and is swingably mounted in a mounting hole 29 of the upper housing. Therefore, according to the safety mechanism S according to the first embodiment of the present invention, not only the time required for transfer as in the conventional safety cap 110 can be saved, but also the safety cover 20 is not lost and the handling is extremely convenient. become.

In the above-described first embodiment, the safety mechanism for switching by rotating the fan-shaped safety cover provided on the panel surface has been described as an example. However, the safety cover having a circular or square shape is straightened. A safety mechanism may be constructed in which the connection terminal is opened and closed inside the housing by operating the button by displacing the connection terminal with a button. Also, the case of multi-function type multimeters such as AC / DC current, voltage, frequency, etc. has been described. The invention can be applied. Although the safety cover is displaced by the contraction force of the coil spring, an expansion force or a driving force other than a spring may be used, and the structure and shape of the test lead are not necessarily limited to the embodiment.

[0021]

[Effect of the invention]

 The present invention relates to an electric measuring instrument for measuring the electric quantity, etc. of a circuit to be measured by replacing a plug of a test lead connected to a connection hole of a connection terminal corresponding to a measuring range provided on a panel of an instrument main body. An electric measuring instrument equipped with a safety mechanism that automatically opens and closes the connection hole for the high-range connection terminal provided on the instrument body. Further, in the above-mentioned item 1, the safety mechanism is provided with a safety cover, and the electric measuring instrument is configured to automatically open and close the connection hole by the safety cover. Further, in the above item 2, an electric measuring instrument in which the safety cover is displayed in red is configured. Further, in the above item 3, an electric measuring instrument was constructed in which the display area for the high range in the measurement range was displayed in a primary color different from the color of the panel and red.

As a result, according to the embodiment, the measurer can be actively alerted to the handling by operating the safety cover and the measurement range in which the color identification is remarkable. For this reason, the measurement operation of the high current by the measurer becomes cautious, and it is possible to avoid occurrence of danger such as burns due to erroneous operation. In addition, if the test lead plug is pulled out after measuring the high current, the safety cover of the safety mechanism will be automatically restored, and no replacement is necessary. Also, since the safety cover is installed inside the main body, there is no worry about losing it.

Therefore, according to the present invention, it is possible to provide an electric measuring instrument which can prevent the erroneous operation of the high current measurement using the test leads, and also can easily perform the measuring operation and handle it easily.

[Brief description of the drawings]

FIG. 1 is a front view showing a configuration of a first embodiment of the present invention.

FIG. 2 is a left side view of FIG.

FIG. 3 is an explanatory diagram showing a configuration of a test lead.

FIG. 4 is a longitudinal sectional view of a main part of the first embodiment.

FIG. 5 is a perspective view of the main part of the first embodiment from the inner surface.

FIG. 6 is an explanatory diagram of the configuration and operation of a conventional electric measuring instrument.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main body 2 Panel 3 Liquid crystal display 4 Shift switch 5 Data hold switch 6 Range hold switch 7 Function switch 8 Common terminal 9 Low current terminal 10 High current terminal 11,12 Test lead 13 Plug 14 Lead wire 15 Gripping part 16 Flange 17 Test Pin 18 Meter cover 19 Holding groove 20 Safety cover 21 Base 22 Sector 23 Shaft 24 Swing cylinder 25 Screw 26 Spring arm 27 Coil spring 28 Standing piece 29 Mounting hole 31 Panel plate 32 Printed circuit board 33 Standing piece 34 Dial frame 35 Enclosure cylinder 36 Envelope 37 Screw Stud 71 Pick S Safety Mechanism

Claims (4)

[Utility model registration claims] 1. An electric measuring instrument for measuring an electric quantity or the like of a circuit to be measured by replacing a plug of a test lead connected to a connection hole of a connection terminal corresponding to a measurement range provided on a panel of an instrument main body, An electric measuring instrument comprising a safety mechanism for automatically opening and closing a connection hole of a connection terminal for a high range provided on an instrument body. 2. The electric measuring instrument according to claim 1, wherein a safety cover is provided in the safety mechanism, and the connection hole is automatically opened and closed by the safety cover. 3. The electric measuring instrument according to claim 2, wherein the safety cover is displayed in red. 4. The electric meter according to claim 3, wherein a display area for the high range in the measurement range is displayed in a primary color different from the color of the panel and red.