Electronic measuring instrument

Abstract

The electronic measuring instrument comprises an electricity meter and a meter pen box, the electricity meter is provided with a first hole site, a second hole site, a third hole site, a fourth hole site and a logic circuit, and the meter pen box comprises a circuit board; one end of the meter pen box is provided with a first terminal, a second terminal, a third terminal and a fourth terminal, the other end of the meter pen box is provided with a pair of test probes, the first to fourth terminals are respectively and correspondingly inserted into the first to fourth hole sites, and the circuit board is coupled to the third and fourth terminals and the pair of test probes; the first terminal and the second terminal respectively comprise a metal elastic sheet, when the first terminal and the second terminal are respectively inserted into the first hole position and the second hole position, a loop is formed between the first hole position and the second hole position through the meter pen box, and whether the meter pen box is inserted into the electric meter or not is judged through the logic circuit. The device is simple in structure, high in measurement efficiency and suitable for measuring conventional current and 30A large current, unexpected damage to an electric meter is avoided, meanwhile, the embedded copper insert is positioned and fastened, and the contact matching reliability of a meter pen box terminal and an electric meter hole site is improved.

Description

Technical Field

[0001] The invention relates to an electronic measuring instrument, in particular to an electronic measuring instrument for measuring large current. Background Art

[0002] A three-meter or clip-on meter is a multi-purpose electronic measuring instrument, generally including an ammeter, a voltmeter, an ohmmeter, etc. It has a variety of different measurement functions and is also called a multimeter, a multimeter, a multimeter, etc.

[0003] First, see Figure 1 , Figure 1 The figure is a schematic diagram of the appearance of a well-known three-way meter. The main body 110 of the three-way meter is provided with four holes 111, 112, 113 and 114. The terminal 121 at one end of the test rod 120 is inserted into the hole 111, and the other test rod is inserted into another hole (not shown). When using the three-way meter, one hand holds a test rod in each hand to measure the object to be measured. Figure 2 , Figure 2 It is a partial enlarged cross-sectional view of a well-known three-way electric meter and a test rod after being combined. When the terminal 121 of the test rod 120 is inserted into the hole 111, the terminal 121 and the inside of the hole 111 are completely connected.

[0004] However, since the hole position of the three-purpose ammeter is a standard component, it can be matched with any universal standard test rod when doing general measurement. Therefore, when the user uses the universal standard test rod to measure a large current (such as 30A), because the large current measurement is designed inside the product and the space limitation of the handheld product itself, the loop resistance through which the current flows is difficult to effectively reduce, and the heat generated cannot be effectively dissipated, which will cause the plastic of the product to deform, thereby causing unexpected harm or damage. The above defects need to be improved. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide an electronic measuring instrument to overcome the defects of existing electronic measuring instruments that heat and deformation may cause damage to the measuring instrument or even other unexpected accidents when measuring large currents.

[0006] The technical solution adopted by the present invention to solve its technical problem is: constructing an electronic measuring instrument, including: an electric meter, the electric meter is provided with a first hole position, a second hole position, a third hole position, a fourth hole position and a logic circuit, and a test pencil box, the test pencil box includes a circuit board, one end of the test pencil box is provided with a first terminal, a second terminal, a third terminal and a fourth terminal, and the other end of the test pencil box is provided with a pair of test probes, wherein the first to fourth terminals are respectively inserted into the first to fourth holes, and the circuit board is coupled to the third and fourth terminals and the pair of test probes; and wherein the first terminal and the second terminal each include a metal spring, when the first terminal and the second terminal are respectively inserted into the first hole position and the second hole position, a loop is formed between the first hole position and the second hole position through the test pencil box, so as to judge whether the electric meter is inserted with the test pencil box through the logic circuit.

[0007] In one embodiment of the present invention, the third hole position and the fourth hole position are used to obtain measurement signals from the pair of test probes to measure the object to be tested.

[0008] In one embodiment of the present invention, the test lead box includes a fuse and a current sampling resistor for transmitting the measurement signal back to the electric meter.

[0009] In one embodiment of the present invention, the first hole and the second hole are further provided with buried copper inlays, and the metal spring sheets are respectively provided on a side surface of the first terminal and the second terminal. When the first terminal and the second terminal are respectively inserted into the first hole and the second hole, the metal spring sheets are respectively in contact with the buried copper inlays.

[0010] In one embodiment of the present invention, the aforementioned electric meter further includes a micro control unit electrically connected to the logic circuit, and the micro control unit determines the measurement mode entered by the electric meter according to the relative high and low relationship of the potentials between the output terminals of the logic circuit.

[0011] In one embodiment of the present invention, the aforementioned electric meter further includes a user interface, and when it is determined that the measurement mode entered by the electric meter is an abnormal measurement mode, a warning message is displayed on the user interface.

[0012] In one embodiment of the present invention, the aforementioned test lead box is suitable for a high current measurement mode with a maximum measurement current of 30A.

[0013] In one embodiment of the present invention, the first hole position is a hole position for measuring current below 10A, the second hole position is a hole position for measuring current below 1A, the third hole position is a grounding terminal, and the fourth hole position is a composite measurement hole position.

[0014] In one embodiment of the present invention, the aforementioned composite measurement hole can measure voltage, resistance and capacitance.

[0015] In one embodiment of the present invention, the buried copper insert includes a protrusion arranged on the wall of the insert from the inside to the outside, and the protrusion is embedded in the plastic material of the hole of the electric meter.

[0016] Compared with the prior art, the electronic measuring instrument of the present invention has the following beneficial effects:

[0017] 1. It has a simple structure and high measurement efficiency. It can be used to measure conventional current and large current. The maximum measurement current is 30A. When large current needs to be measured, a large current measuring pen box is used in combination with an ammeter to avoid unexpected damage.

[0018] 2. A protrusion extending from the inside to the outside is provided on the side wall of the buried copper insert, and the protrusion is embedded with the plastic material of the meter hole to ensure that the buried copper insert is firmly and reliably positioned, thereby improving the reliability of the contact and matching between the terminal of the test lead box and the buried copper insert of the meter hole. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the appearance of an existing three-purpose electric meter.

[0020] Figure 2 It is a partially enlarged cross-sectional view of a combination of an existing three-purpose electric meter and a test rod.

[0021] Figure 3 It is a schematic diagram of the appearance of the electronic measuring instrument of the present invention.

[0022] Figure 4 The present invention is a partially enlarged cross-sectional view of a specific embodiment of a combination of a test lead box of an electronic measuring instrument and an electric meter using the test lead box.

[0023] Figure 5 It is a side schematic diagram of a test pencil box in an electronic measuring instrument of the present invention. DETAILED DESCRIPTION

[0024] The present invention will be described in detail below in conjunction with typical embodiments and the accompanying drawings. The same reference numerals in each figure indicate the same or similar parts. Although the specification discloses typical embodiments, there may be other embodiments that do not depart from the spirit and scope of the present invention without changing the embodiments of the specification. The following detailed description does not limit the present invention, and the scope of protection of the present invention is defined by the claims and their equivalent technical solutions.

[0025] Description of the figure numbers in the manual:

[0026] 110: main body; 111, 112, 113, 114: hole positions;

[0027] 120: test rod; 121: terminal;

[0028] 1: Electric meter; 11, 12, 13, 14: Holes; 15: Knob; 16: Display;

[0029] 2: Test lead box; 21, 22, 23, 24: Terminals; 25, 26: Test probes;

[0030] 251, 261: a first end of a test probe; 252, 262: a second end of a test probe;

[0031] 101: buried copper insert; 1011: buried copper insert protrusion

[0032] 211: Metal shrapnel.

[0033] See also Figure 3 , Figure 3 The electronic measuring instrument of the present invention comprises an electric meter 1 and a test pen box 2. The electric meter 1 is, for example, a composite digital electric meter. The electric meter 1 comprises holes 11, 12, 13 and 14, a knob 15 and a display 16. The knob 15 is used to select a measurement mode (such as a current mode, a voltage mode, a resistance mode, etc.). The display 16 can display the measurement results according to the measurement mode.

[0034] One end of the test lead box 2 is provided with four terminals 21, 22, 23 and 24, and the terminals 21, 22, 23 and 24 can be respectively plugged into the holes 11, 12, 13 and 14 of the electric meter 1. In this embodiment, the hole 11 is a large current (below 10A) measurement hole, the hole 12 is a small current (below 1A) measurement hole, the hole 13 is a ground terminal, and the hole 14 is a composite measurement (voltage / resistance / capacitance) hole.

[0035] The other end of the test lead box 2 is connected to a pair of test probes, which are composed of test probes 25 and 26. The first ends 251 and 261 of the test probes 25 and 26 are connected to the test lead box 2 respectively, and the second ends 252 and 262 of the test probes 25 and 26 are used to contact the object to be tested for measurement. The test lead box 2 includes a fuse (withstanding current 30A) and a current sampling resistor (not shown) to transmit the measurement signal back to the electric meter 1. The holes 13 and 14 of the electric meter 1 are used to obtain the measurement signal from the test probes 25 and 26 to measure the object to be tested. The test probes 25 and 26 can be needle-type, clip-type or probe rod-type. In this embodiment, the test probes 25 and 26 are crocodile clips as an example.

[0036] See also Figure 4 , Figure 4It is a partially enlarged cross-sectional view showing a specific embodiment of the combination of the test lead box of the present invention and the electric meter using the test lead box. A metal spring 211 is provided on one side of the terminal 21 of the test lead box 2 (similarly, a metal spring is also provided on one side of the terminal 22). The material of the metal spring 211 is, for example, copper or other commonly used conductive materials. The hole 11 is provided with buried copper inserts 101 on two opposite sides respectively (similarly, the hole 12 is also provided with a buried copper insert). Figure 5 1 is a side view of a test lead box of an electronic measuring instrument of the present invention. In this embodiment, the electric meter 1 further includes a logic circuit for detecting a current measurement mode, and a micro control unit (not shown) electrically connected to the logic circuit. The test lead box 2 further includes a circuit board (not shown), which is coupled to the terminals 23, 24 and the test probes 25, 26. Please refer to Figure 4 and Figure 5 When the terminal 21 of the test lead box 2 is inserted into the hole 11 of the electric meter 1, the metal spring 211 in the terminal 21 contacts the buried copper insert 101 of the hole 11 of the electric meter 1 to form a single-sided conduction. Similarly, the metal spring in the terminal 22 inserted in the hole 12 also contacts the buried copper insert of the hole 12 to form a single-sided conduction, and the terminal 21 and the terminal 22 are directly short-circuited via a metal (not shown). When the test lead box 2 is inserted into the electric meter 1, a loop is formed between the holes 11 and 12 via the test lead box 2, thereby changing the logic state. Accordingly, the logic circuit of the electric meter 1 determines whether the electric meter 1 is inserted with the test lead box 2. In the embodiment of the present invention, the test lead box 2 is suitable for a large current measurement mode with a maximum measurement current of 30A, and the object to be measured can be measured via the test probes 25 and 26.

[0037] like Figure 4 As shown, a protrusion 1011 extending from the inside to the outside is provided on the side wall of the buried copper insert 101. During the injection molding process of the shell of the electric meter 1, the protrusion 1011 is embedded with the plastic material of the electric meter hole, ensuring that the buried copper insert 101 is positioned firmly and reliably, and helping to improve the reliability of the contact and matching between the test lead box terminal 211 and the buried copper insert 101 in the electric meter hole. The protrusion 1011 can be in the shape of a structure including but not limited to a dot shape, a ring shape, etc., and one or more protrusions 1011 can be provided as needed.

[0038] The above logic circuit is further described below. For example, a logic circuit capable of detecting three current measurement modes (mA, A, 30A) is used to detect which mode the current meter should enter. The first to third output terminals of the logic circuit respectively generate high potential or low potential in different detection states, as shown in Table 1.

[0039]

[0040] Table 1

[0041] For example, when no test probe is inserted, the potential of the first output terminal of the logic circuit is high, the potential of the second output terminal is low, and the potential of the third output terminal is high (H is the abbreviation for high potential, and L is the abbreviation for low potential). The above potential signal will be transmitted back to the micro control unit (MCU) of the meter so that the software determines that this is an abnormal measurement mode. At this time, a warning slogan appears on the user interface (such as display 16) to remind the user (for example, warning message 2: inserted in the current measurement hole position). The warning messages corresponding to other different detection states include, for example, warning message 1 (inserted in the voltage measurement hole position) and warning message 3 (do not insert multiple probes). Therefore, according to the different potentials under the above detection states, a coding combination that can be read by the micro control unit is generated to determine which measurement mode the current meter has entered.

[0042] One of the features of the present invention is that while maintaining the original measurement function and the original detection function of the first to fourth holes of the electric meter and meeting the requirements of high voltage protection of international safety regulations, an additional detection function is added to correctly detect external expansion components to achieve functional expansion.

[0043] The second feature of the present invention is that a protrusion extending from the inside to the outside is provided on the side wall of the buried copper insert, and the protrusion is engaged with the plastic material of the meter hole to ensure that the buried copper insert is positioned firmly and reliably, thereby improving the reliability of the contact and cooperation between the terminal of the test lead box and the buried copper insert in the meter hole.

Claims

1. An electronic measuring instrument comprising: An electric meter, the electric meter is provided with a first hole position, a second hole position, a third hole position, a fourth hole position, a logic circuit and a meter pen box; It is characterized in that the test lead box includes a circuit board, one end of the test lead box is provided with a first terminal, a second terminal, a third terminal and a fourth terminal, and the other end of the test lead box is provided with a pair of test probes, wherein the first to fourth terminals are respectively inserted into the first to fourth holes, and the circuit board is coupled to the third terminal, the fourth terminal and the pair of test probes; the first terminal and the second terminal each include a metal spring, when the first terminal and the second terminal are respectively inserted into the first hole and the second hole, a loop is formed between the first hole and the second hole through the test lead box, so as to judge whether the electric meter is inserted with the test lead box through the logic circuit.

2. The electronic measuring instrument according to claim 1, characterized in that The third hole position and the fourth hole position are used to obtain measurement signals from the pair of test probes to measure the object to be measured.

3. The electronic measuring instrument according to claim 2, characterized in that: The test lead box includes a fuse and a current sampling resistor, which are used to transmit the measurement signal back to the electric meter.

4. The electronic measuring instrument according to claim 1, characterized in that: The first hole position and the second hole position are provided with buried copper inlays, and the metal spring pieces are respectively provided on one side of the first terminal and the second terminal. When the first terminal and the second terminal are respectively inserted into the first hole position and the second hole position, the metal spring pieces are respectively in contact with the buried copper inlays.

5. The electronic measuring instrument according to claim 1, characterized in that: The electric meter includes a micro control unit electrically connected to the logic circuit. The micro control unit determines the measurement mode entered by the electric meter according to the relative high and low relationship of the potentials between the output terminals of the logic circuit.

6. The electronic measuring instrument according to claim 5, characterized in that The electric meter includes a user interface. When it is determined that the measurement mode entered by the electric meter is an abnormal measurement mode, the user interface displays a warning message.

7. The electronic measuring instrument according to claim 1, characterized in that: The test lead box is suitable for a large current measurement mode with a maximum measurement current of 30A.

8. The electronic measuring instrument according to claim 1, characterized in that: The first hole position is a hole position for measuring current below 10A, the second hole position is a hole position for measuring current below 1A, the third hole position is a grounding terminal, and the fourth hole position is a composite measurement hole position.

9. The electronic measuring instrument according to claim 8, characterized in that The composite measurement hole can measure voltage, resistance and capacitance.

10. The electronic measuring instrument according to claim 4, characterized in that: The buried copper insert comprises a protrusion arranged on the wall of the insert from the inside to the outside, and the protrusion is embedded with the plastic material of the hole of the electric meter.

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