Automatic power-off device for digital voltmeter

Abstract

The utility model relates to an automatic power-off device of digital voltmeter belongs to automatic power-off device field, including digital display panel, body, power end, electromagnet, wire one, input electrode piece, wire two, secondary conductive block, main conductive block, one side of body is fixedly connected with mounting box, in the measurement process of digital voltmeter: electromagnet cooperation with magnetic disc, when current moment over withstand scope, electromagnet generates magnetic force, hydraulic oil cooperation with piston buffer the time delay of conductive core and main conductive block and separates, adapt to current fluctuation, guarantee the continuous operation of measurement data, magnetic disc cooperation with magnetic ring, meet high overcurrent, utilize the magnetic force of large current and make magnetic ring separate from magnetic disc, and conductive core and main conductive block separate instantaneously, guarantee the safe use, tension spring two cooperation with mounting plate, when conductive core and main conductive block separate, drive locking rod and insert the physical isolation therebetween, and maintenance personnel can visually confirm power-off, guarantee the safe use.

Description

Technical Field

[0001] This invention relates to the field of automatic power-off devices, and more particularly to an automatic power-off device for a digital voltmeter. Background Technology

[0002] A digital voltmeter is an instrument that uses digital measurement technology to convert continuous analog quantities into discrete digital forms for display. Traditional pointer voltmeters have limited functionality, low accuracy, and inconvenient readings, failing to meet the demands of the digital age. Digital voltmeters using microcontrollers offer advantages such as high accuracy, strong anti-interference capabilities, high scalability, easy integration, and real-time communication with PCs. They are widely used in intelligent measurement fields such as electronic and electrical measurements, industrial automation instruments, and automatic testing systems.

[0003] Because the voltage / current withstand capabilities of components such as the internal ADC chip and microprocessor of a digital voltmeter are limited, a sudden high voltage or short circuit in the circuit under test may burn out the core components of the DVM, leading to high costs for high-frequency repair or instrument replacement. Therefore, an automatic power-off device is needed to ensure stable measurement by the digital voltmeter. Existing automatic power-off devices for digital voltmeters will directly cut off the power to the digital voltmeter when the input current exceeds the tolerance range. However, in industrial scenarios such as motor start-up and shutdown, capacitor discharge, etc., due to load switching or power grid fluctuations, the input current may only temporarily exceed the tolerance range. In this case, the power-off device will still indiscriminately cut off the power, interrupting the measurement process. Especially when long-term test data is required, this will cause problems for the measurement of the digital voltmeter and is not conducive to the continuous use of the digital voltmeter. Summary of the Invention

[0004] The purpose of this invention is to solve the problem that existing automatic power-off devices cannot distinguish between transient interference and real faults, and to propose an automatic power-off device for a digital voltmeter.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] An automatic power-off device for a digital voltmeter includes a digital display panel, a body, a power supply terminal, an electromagnet, a first wire, input electrode plates, second wires, secondary conductive blocks, and a main conductive block. A mounting box is fixedly connected to one side of the body, and a support shell is provided inside the mounting box. One end of the support shell is fixedly connected to one side wall of the body. The electromagnet is fixedly mounted on one inner wall of the mounting box. Two input electrode plates are respectively mounted on the upper and lower surfaces of the mounting box. Both ends of the first wire are connected to the two input electrode plates, and the first wire is connected in series with the electromagnet. One end of each of the two second wires is connected in series with the electromagnet. Two secondary conductive blocks are respectively mounted on the upper and lower inner walls of the support shell, and the other ends of the two second wires are connected to the secondary conductive blocks.

[0007] The support shell is equipped with a time delay buffer component to provide a time delay buffer when there is a brief current overcurrent, so as to avoid directly interrupting the measurement process.

[0008] The outer wall of the support shell is provided with an overcurrent breaking component to quickly detach and separate when encountering a high overcurrent, thus avoiding the possibility of direct breakdown by a large current.

[0009] The mounting box is equipped with a release and locking component to enable rapid physical isolation after power failure, and the power failure status can be visually confirmed.

[0010] Furthermore, the delay buffer component includes a conductive core, and the upper and lower surfaces of the conductive core slide against the sides of the two secondary conductive blocks respectively. The main conductive block is electrically connected to the body. A hydraulic cylinder is fixedly connected to the outer wall of the conductive core facing the electromagnet, and a hydraulic rod is slidably connected to the inner wall of the hydraulic cylinder. Hydraulic chambers are symmetrically opened on the inner wall of the hydraulic cylinder, and a piston is fixedly connected to the end of the hydraulic rod away from the electromagnet. The outer wall of the piston slides and matches the inner wall of the hydraulic chamber, and a flow hole is opened through the inner wall of the hydraulic chamber.

[0011] Furthermore, a magnetic disk is fixedly connected to one end of the hydraulic rod facing the electromagnet, and a tension spring is fixedly connected to the end face of the magnetic disk away from the electromagnet. The other end of the tension spring is fixedly connected to the end of the hydraulic cylinder facing the electromagnet.

[0012] Furthermore, the overcurrent cutoff component includes a magnetic ring, and connecting plates are symmetrically fixedly connected to the outer walls of both sides of the magnetic ring. Each of the two connecting plates has a limiting groove inside, and a slider is slidably connected to the inner wall of the limiting groove. A sliding rod is fixedly connected to the outer wall of the slider away from the electromagnet. A second spring is fixedly connected to the outer wall of the two sliders away from each other. One end of the two second springs away from each other is fixedly connected to the inner wall of the limiting groove. A blocking block is slidably connected to the outer wall of each sliding rod. Limiting grooves are opened through the outer walls of both sides of the support shell corresponding to the blocking blocks, and the outer wall of the blocking block slides in contact with the inner wall of the limiting groove.

[0013] Furthermore, a sliding plate is fixedly connected to the end of the sliding rod away from the electromagnet, and the outer wall of the two sliding plates that are close to each other slides against the outer walls of the two sides of the support shell. Guide blocks are symmetrically fixedly connected to the outer walls of the two sides of the support shell corresponding to the sliding plates, and the outer wall of the guide block facing the sliding plate is inclined.

[0014] Furthermore, the inner wall of the magnetic ring is symmetrically provided with grooves, and a spring is fixedly connected to the inner wall of the groove. A locking block is fixedly connected to the other end of the spring, and the outer wall of the locking block slides against the inner wall of the groove. The locking block forms a telescopic structure with the groove through the spring. The outer wall of the magnetic disk is provided with a slot corresponding to the locking block, and the end of the locking block facing the slot is truncated cone-shaped.

[0015] Furthermore, the support shell has an adsorption cavity extending through the side facing the electromagnet. The outer wall of the magnetic ring slides against the inner wall of the adsorption cavity. The support shell has symmetrically formed sliding grooves on the side facing the electromagnet. The outer wall of the connecting plate slides against the inner wall of the sliding grooves. A reset frame is slidably mounted on the top of the support shell, and a spring is fixedly connected to the bottom of the reset frame. The bottom of the spring is fixedly connected to the top of the mounting box. The two ends of the bottom of the reset frame are inclined surfaces corresponding to the connecting plate.

[0016] Furthermore, the release mechanism includes a locking rod, the outer wall of which is slidably connected to the inner wall of the mounting box. A second tension spring is fitted to the outer wall of the locking rod, and a mounting plate is fixedly connected to the outer wall of the locking rod. One end of the second tension spring is fixedly connected to one side wall of the mounting plate, and the other end of the second tension spring is fixedly connected to one side outer wall of the support shell. The end of the locking rod facing the conductive core is inclined, and a reset plate is fixedly connected to the other end of the locking rod.

[0017] Compared with existing technologies, the above solution has the following advantages:

[0018] 1. During the measurement process of a digital voltmeter, the electromagnet and magnetic disk work together to generate magnetic force when the current briefly exceeds the tolerance range. The hydraulic oil and piston work together to delay and buffer the separation time between the conductive core and the main conductive block. This allows the voltmeter to adapt to short-term fluctuations in the current during the measurement process, avoids direct interruption of the measurement process, and helps to ensure the continuous operation of measurement data.

[0019] 2. During the measurement process of the digital voltmeter, the magnetic disk and magnetic ring work together to avoid the possibility of direct breakdown when encountering high overcurrent. The large magnetic force generated by the high current allows the magnetic ring to detach from the magnetic disk, thereby instantly separating the conductive core from the main conductive block. This allows for reasonable switching based on the magnitude of the overcurrent, thus helping to ensure the safety of the digital voltmeter.

[0020] 3. During the measurement process of the digital voltmeter, the cooperation between the tension spring and the mounting plate allows the locking rod to quickly engage between the conductive core and the main conductive block for physical isolation when the conductive core is separated from the main conductive block. Furthermore, maintenance personnel can visually confirm the power off by checking the position of the locking rod, which helps ensure the safety of using this digital voltmeter. Attached Figure Description

[0021] Figure 1 This is a three-dimensional structural diagram of an automatic power-off device for a digital voltmeter proposed in this invention.

[0022] Figure 2 This is a rear-view three-dimensional structural diagram of the automatic power-off device for a digital voltmeter proposed in this invention.

[0023] Figure 3 This is a three-dimensional structural diagram of the internal structure of the mounting box of the automatic power-off device for a digital voltmeter proposed in this invention.

[0024] Figure 4 This is a three-dimensional structural diagram of the internal support shell of an automatic power-off device for a digital voltmeter proposed in this invention.

[0025] Figure 5 This is a three-dimensional structural diagram of the internal structure of the hydraulic cylinder of an automatic power-off device for a digital voltmeter proposed in this invention.

[0026] Figure 6 This invention proposes an automatic power-off device for a digital voltmeter. Figure 5 An enlarged 3D structural diagram at point A in the middle;

[0027] Figure 7 This is a three-dimensional structural diagram illustrating the connection relationship between the connecting plate and the sliding rod of the automatic power-off device for a digital voltmeter proposed in this invention.

[0028] Figure 8 This invention proposes an automatic power-off device for a digital voltmeter. Figure 7 Enlarged 3D structural diagram at point B;

[0029] Figure 9 This is a three-dimensional structural diagram illustrating the positional relationship between the locking rod and the conductive core of an automatic power-off device for a digital voltmeter proposed in this invention.

[0030] In the diagram: 1. Digital display panel; 2. Main body; 3. Power supply terminal; 4. Mounting box; 5. Support shell; 9. Electromagnet; 10. Wire 1; 11. Input electrode plate; 12. Wire 2; 13. Secondary conductive block; 14. Main conductive block; 15. Reset frame; 16. Spring 1; 6. Delay buffer component; 601. Conductive core; 602. Hydraulic cylinder; 603. Hydraulic rod; 604. Piston; 605. Hydraulic chamber; 606. Flow hole; 607. Magnetic disk; 608. Tension spring 1; 7. Flow rate cutoff component; 701, magnetic ring; 702, connecting plate; 703, limiting groove; 704, slider; 705, sliding rod; 706, spring two; 707, blocking block; 708, limiting groove; 709, sliding plate; 710, guide block; 711, groove; 712, spring three; 713, locking block; 714, locking groove; 715, adsorption chamber; 716, sliding groove; 8, disengagement jamming component; 801, locking rod; 802, tension spring two; 803, mounting plate; 804, reset plate. Detailed Implementation

[0031] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0032] In the description of this invention, it should be understood that the terms "upper," "lower," "top surface," "bottom surface," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the indicated position or element must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are only used to distinguish an entity or operation from another entity or operation, and do not require or imply any actual relationship, order, or relative importance between these entities or operations.

[0033] Example 1, referring to Figures 1-9An automatic power-off device for a digital voltmeter includes a digital display panel 1, a body 2, a power supply terminal 3, an electromagnet 9, a first wire 10, input electrode plates 11, second wires 12, secondary conductive blocks 13, and a main conductive block 14. A mounting box 4 is fixedly connected to one side of the body 2, and a support shell 5 is provided inside the mounting box 4. One end of the support shell 5 is fixedly connected to one side wall of the body 2. The electromagnet 9 is fixedly installed on one side inner wall of the mounting box 4. Two input electrode plates 11 are respectively installed on the upper and lower surfaces of the mounting box 4. The two ends of the first wire 10 are respectively connected to the two input electrode plates 11. The first wire 10 is connected in series with the electromagnet 9. One end of the two second wires 12 is connected in series with the electromagnet 9. Two secondary conductive blocks 13 are respectively installed on the upper and lower inner walls of the support shell 5. The other ends of the two second wires 12 are connected to the secondary conductive blocks 13.

[0034] In this embodiment, a delay buffer component 6 is provided inside the support shell 5. The delay buffer component 6 includes a conductive core 601, and the upper and lower surfaces of the conductive core 601 are respectively in contact with and slide against the sides of the two secondary conductive blocks 13. The main conductive block 14 is electrically connected to the body 2. A hydraulic cylinder 602 is fixedly connected to the outer wall of the conductive core 601 facing the electromagnet 9, and a hydraulic rod 603 is slidably connected to the inner wall of the hydraulic cylinder 602. Hydraulic chambers 605 are symmetrically opened on the inner wall of the hydraulic cylinder 602, and a piston 604 is fixedly connected to the end of the hydraulic rod 603 away from the electromagnet 9. The outer wall of the piston 604 slides and matches the inner wall of the hydraulic chamber 605. A flow hole 606 is opened through the inner wall of the hydraulic chamber 605.

[0035] Next, when using this device, a mounting box 4 is fixedly connected to one side of the main body 2, and a support shell 5 is provided inside the mounting box 4. One end of the support shell 5 is fixedly connected to one side wall of the main body 2. The electromagnet 9 is fixedly installed on the inner wall of one side of the mounting box 4. Two input electrode plates 11 are respectively installed on the upper and lower surfaces of the mounting box 4. The two ends of the first wire 10 are respectively connected to the two input electrode plates 11. The first wire 10 is connected in series with the electromagnet 9. One end of each of the two second wires 12 is connected in series with the electromagnet 9. Two secondary conductive blocks 13 are respectively installed on the upper and lower inner surfaces of the support shell 5. The other ends of the two wires 12 are connected to the secondary conductive block 13. The upper and lower surfaces of the conductive core 601 slide against the sides of the two secondary conductive blocks 13. The main conductive block 14 is electrically connected to the body 2. Thus, through the contact between the main conductive block 14 and the conductive core 601, the two secondary conductive blocks 13 are electrically connected to the main conductive block 14. Then, through the cooperation of the wires 12 and the wires 10, the two wire clamps can be connected to the two input electrode plates 11 respectively. At this time, the two wire clamps can be clamped at the position to be measured.

[0036] Next, during the measurement process, the current flowing through the coil of the conductor 10 and the electromagnet 9 are connected in series, generating magnetic force. Then, a hydraulic cylinder 602 is fixedly connected to the outer wall of the conductive core 601 facing the electromagnet 9, and a hydraulic rod 603 is slidably connected to the inner wall of the hydraulic cylinder 602. Hydraulic chambers 605 are symmetrically opened on the inner wall of the hydraulic cylinder 602, and a piston 604 is fixedly connected to the end of the hydraulic rod 603 away from the electromagnet 9. The outer wall of the piston 604 slides and matches the inner wall of the hydraulic chamber 605. A flow hole 606 is opened through the inner wall of the hydraulic chamber 605. A magnetic disk 607 is fixedly connected to the end of the hydraulic rod 603 facing the electromagnet 9, and a tension spring 608 is fixedly connected to the end of the magnetic disk 607 away from the electromagnet 9. The other end of the tension spring 608 is fixedly connected to the end of the hydraulic cylinder 602 facing the electromagnet 9. Under normal current flow conditions, the magnetic force generated is less than the elastic force of the tension spring 608, thereby limiting the position of the piston 604.

[0037] When the current experiences a brief overcurrent, i.e. exceeds the normal range, the magnetic force will also increase synchronously, causing the magnetic disk 607 to move towards the electromagnet 9, thereby driving the piston 604 to squeeze the hydraulic oil in the hydraulic chamber 605. With the cooperation of several tiny flow holes 606, a buffering effect is formed, so that the piston 604 needs to completely squeeze the hydraulic oil located on the right side of the hydraulic chamber 605 into the left hydraulic chamber 605 in order to separate the conductive core 601 from the main conductive block 14.

[0038] In this process, the separation time between the conductive core 601 and the main conductive block 14 is delayed and buffered to adapt to the short-term fluctuations in current during the measurement process and avoid directly interrupting the measurement process. At the same time, when the current recovers, it is restored by the tension spring 608, which helps to ensure the continuous operation of measurement data.

[0039] In this embodiment, the outer wall of the support shell 5 is provided with an overflow velocity cutoff component 7. The overflow velocity cutoff component 7 includes a magnetic ring 701, and connecting plates 702 are symmetrically fixedly connected to the outer walls of both sides of the magnetic ring 701. A limiting groove 703 is opened inside the two connecting plates 702, and a slider 704 is slidably connected to the inner wall of the limiting groove 703. A sliding rod 705 is fixedly connected to the outer wall of the slider 704 away from the electromagnet 9. A second spring 706 is fixedly connected to the outer wall of the two sliders 704 away from each other. One end of the two second springs 706 away from each other is fixedly connected to the inner wall of the limiting groove 703. A blocking block 707 is slidably connected to the outer wall of the two sliding rods 705. A limiting groove 708 is opened through the two outer walls of the support shell 5 corresponding to the blocking block 707, and the outer wall of the blocking block 707 is in contact with and slides against the inner wall of the limiting groove 708.

[0040] Next, to achieve the delay effect and the effect of rapid separation when encountering high overcurrent, the overcurrent fast-break component 7 includes a magnetic ring 701, and connecting plates 702 are symmetrically fixedly connected to the outer walls of both sides of the magnetic ring 701. Each of the two connecting plates 702 has a limiting groove 703 inside, and a slider 704 is slidably connected to the inner wall of the limiting groove 703. A sliding rod 705 is fixedly connected to the outer wall of the slider 704 on the side away from the electromagnet 9. A second spring 706 is fixedly connected to the outer wall of the two sliders 704 on the side away from each other. The ends of the two springs 706 that are away from each other are fixed... Connected to the inner wall of the limiting groove 703, the outer walls of the two slide rods 705 are slidably connected with blocking blocks 707. The outer walls of both sides of the support shell 5 are provided with limiting grooves 708 through the blocking blocks 707. The outer walls of the blocking blocks 707 slide against the inner walls of the limiting grooves 708. Under normal circumstances, the elastic force of the second spring 706 makes the two sliders 704 close to each other. Then, through the cooperation of the slide rods 705, the two blocking blocks 707 are driven to pass through the limiting grooves 708 and extend into the support shell 5 to forcibly limit the current position of the conductive core 601.

[0041] During the process of piston 604 squeezing hydraulic oil, the current position of conductive core 601 is restricted by blocking block 707 to achieve a delay effect. Then, grooves 711 are symmetrically opened on the inner wall of magnetic ring 701, and spring three 712 is fixedly connected to the inner wall of groove 711. The other end of spring three 712 is fixedly connected to a locking block 713, and the outer wall of locking block 713 slides against the inner wall of groove 711. Locking block 713 forms a telescopic structure with groove 711 through spring three 712. The outer wall of magnetic disk 607 is provided with locking groove 714 corresponding to locking block 713, and the end of locking block 713 facing locking groove 714 is frustoconical. Thus, when there is a small overcurrent, the magnetic ring 701 and magnetic disk 607 will move synchronously towards electromagnet 9 through the cooperation of locking block 713 and locking groove 714.

[0042] Next, a sliding plate 709 is fixedly connected to one end of the slide rod 705 away from the electromagnet 9. The outer walls of the two sliding plates 709 that are close to each other slide against the outer walls of the two sides of the support shell 5. Guide blocks 710 are symmetrically fixedly connected to the outer walls of the two sides of the support shell 5 corresponding to the sliding plates 709. The outer wall of the guide block 710 facing the sliding plate 709 is inclined. Thus, during the synchronous movement, the two sliding plates 709 will be moved synchronously towards the guide block 710. If the current does not return to normal after a certain delay, the inclined surface of the guide block 710 will cause the two sliding plates 709 to move away from each other after contacting the guide block 710. This will cause the blocking block 707 to release the restriction on the conductive core 601. At this time, the hydraulic cylinder 602 will be driven by the piston 604 to synchronously separate the conductive core 601 from the main conductive block 14, so as to adapt to the short-term fluctuation of the current during the measurement process.

[0043] Furthermore, when encountering a high overcurrent, the large magnetic force generated by the high current is used to simultaneously and strongly magnetically attract the magnetic disk 607 and the magnetic ring 701. Because the magnetic disk 607 cannot move quickly due to the drag of the hydraulic oil, the magnetic ring 701 is disengaged from the magnetic disk 607 under strong magnetic attraction and quickly comes into contact with the electromagnet 9. This quickly releases the obstruction of the blocking block 707 on the conductive core 601. Correspondingly, the conductive core 601 is now free from the obstruction of the blocking block 707. When the piston 604 squeezes the hydraulic oil, the hydraulic cylinder 602 directly drives the conductive core 601 to separate from the main conductive block 14 without the need for a delay step. This allows for reasonable switching based on the magnitude of the overcurrent, which helps ensure the safety of this digital voltmeter.

[0044] Next, during the reset after troubleshooting, an adsorption cavity 715 is provided through the support shell 5 on the side facing the electromagnet 9. The outer wall of the magnetic ring 701 slides against the inner wall of the adsorption cavity 715. A sliding groove 716 is symmetrically provided on the support shell 5 on the side facing the electromagnet 9. The outer wall of the connecting plate 702 slides against the inner wall of the sliding groove 716. A reset frame 15 is slidably mounted on the top of the support shell 5, and a spring 16 is fixedly connected to the bottom of the reset frame 15. The bottom of the spring 16 is fixedly connected to the top of the mounting box 4. The two ends of the bottom of the reset frame 15 are inclined relative to the connecting plate 702, thus ensuring the stability of the magnetic ring 701 during sliding through the adsorption cavity 715. After the magnetic ring 701 and the magnetic disk 607 are separated, the magnetic ring 701 is on the left side of the magnetic disk 607. At this time, by manually pressing the reset frame 15, the inclined surfaces of the two ends of the bottom of the reset frame 15 can be used to squeeze the connecting plate 702, causing the magnetic ring 701 to move back to its original position. Then, the locking block 713 is used to squeeze and push the magnetic disk 607 back to its original position, so that the conductive core 601 and the main conductive block 14 are in contact again. After contact, the conductive core 601 can no longer move, so the locking block 713 is squeezed and retracted into the slot 714 of the magnetic disk 607, completing the engagement connection between the magnetic disk 607 and the magnetic ring 701.

[0045] In this embodiment, the mounting box 4 is provided with a release jamming component 8, which includes a locking rod 801. The outer wall of the locking rod 801 is slidably connected to the inner wall of the mounting box 4. A tension spring 802 is attached to the outer wall of the locking rod 801, and a mounting plate 803 is fixedly connected to the outer wall of the locking rod 801. One end of the tension spring 802 is fixedly connected to one side wall of the mounting plate 803, and the other end of the tension spring 802 is fixedly connected to one side outer wall of the support shell 5. The end of the locking rod 801 facing the conductive core 601 is inclined, and a reset plate 804 is fixedly connected to the other end of the locking rod 801.

[0046] Then, under normal circumstances, the inclined end of the locking lever 801 is pressed against the gap between the conductive core 601 and the main conductive block 14 by the tension spring 802. This allows the locking lever 801 to quickly engage with the conductive core 601 and the main conductive block 14 when the conductive core 601 and the main conductive block 14 are separated, thus providing physical isolation. Furthermore, maintenance personnel can visually confirm the power outage by observing the position of the locking lever 801, which helps ensure the safety of this digital voltmeter.

[0047] The working principle of this invention is as follows: First, the two wire clamps are connected to the two input electrode plates 11 respectively to achieve communication. At this time, the two wire clamps can be used to clamp the position to be measured. During the measurement process, the current flowing through the coil can generate magnetic force by connecting the wire 10 in series with the electromagnet 9.

[0048] When a brief overcurrent occurs, i.e., when it exceeds the normal range, the magnetic force will also increase synchronously, causing the magnetic disk 607 to move towards the electromagnet 9. This will drive the piston 604 to squeeze the hydraulic oil in the hydraulic chamber 605. With the cooperation of several tiny flow holes 606, a buffering effect is formed, so that the piston 604 needs to completely squeeze the hydraulic oil on the right side of the hydraulic chamber 605 into the left hydraulic chamber 605 in order to separate the conductive core 601 from the main conductive block 14. This delays and buffers the separation time between the conductive core 601 and the main conductive block 14, so as to adapt to the brief current fluctuations during the measurement process and avoid directly interrupting the measurement process. At the same time, when the current recovers, it is restored by the tension spring 608, which helps to ensure the continuous operation of measurement data.

[0049] During a small overcurrent, the magnetic ring 701 and the magnetic disk 607 move synchronously toward the electromagnet 9 through the cooperation of the card block 713 and the card slot 714. During the synchronous movement, the two slide plates 709 move synchronously toward the guide block 710. If the current does not return to normal after a certain delay, the inclined surface of the guide block 710 makes the two slide plates 709 move away from each other after contacting the guide block 710, thereby causing the blocking block 707 to release the restriction on the conductive core 601. At this time, the hydraulic cylinder 602, under the squeezing action of the piston 604, synchronously drives the conductive core 601 to separate from the main conductive block 14, so as to adapt to the short-term fluctuations in current during the measurement process.

[0050] Furthermore, when encountering a high overcurrent, the large magnetic force generated by the high current is used to simultaneously and strongly magnetically attract the magnetic disk 607 and the magnetic ring 701. Because the magnetic disk 607 cannot move quickly due to the drag of the hydraulic oil, the magnetic ring 701 is disengaged from the magnetic disk 607 under strong magnetic attraction and quickly comes into contact with the electromagnet 9. This quickly releases the obstruction of the blocking block 707 on the conductive core 601. Correspondingly, the conductive core 601 is now free from the obstruction of the blocking block 707. When the piston 604 squeezes the hydraulic oil, the hydraulic cylinder 602 directly drives the conductive core 601 to separate from the main conductive block 14 without the need for a delay step. This allows for reasonable switching based on the magnitude of the overcurrent, which helps ensure the safety of this digital voltmeter.

[0051] Next, during the reset after troubleshooting, after the magnetic ring 701 and the magnetic disk 607 separate, the magnetic ring 701 is on the left side of the magnetic disk 607. At this time, by manually pressing the reset frame 15, the inclined surfaces of the two ends of the bottom of the reset frame 15 can be used to squeeze the connecting plate 702, causing the magnetic ring 701 to move back to its original position. Then, the locking block 713 is used to squeeze and push the magnetic disk 607 back to its original position, so that the conductive core 601 and the main conductive block 14 are in contact again. After contact, the conductive core 601 can no longer move, so the locking block 713 is squeezed and retracted into the slot 714 of the magnetic disk 607, completing the engagement connection between the magnetic disk 607 and the magnetic ring 701.

[0052] Then, under normal circumstances, the inclined end of the locking lever 801 is pressed against the gap between the conductive core 601 and the main conductive block 14 by the tension spring 802. This allows the locking lever 801 to quickly engage with the conductive core 601 and the main conductive block 14 when the conductive core 601 and the main conductive block 14 are separated, thus providing physical isolation. Furthermore, maintenance personnel can visually confirm the power outage by observing the position of the locking lever 801, which helps ensure the safety of this digital voltmeter.

[0053] While the present invention has been disclosed above, it is not limited thereto. Those skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. An automatic power-off device for a digital voltmeter, comprising a body (2), an electromagnet (9), a second conductor (12), a secondary conductive block (13), and a main conductive block (14), characterized in that, A mounting box (4) is fixedly connected to one side of the body (2), and a support shell (5) is provided inside the mounting box (4). One end of the support shell (5) is fixedly connected to one side wall of the body (2). The electromagnet (9) is fixedly installed on one side of the inner wall of the mounting box (4). One end of the two wires (12) is connected in series with the electromagnet (9). The two secondary conductive blocks (13) are respectively installed on the upper and lower inner walls of the support shell (5). The other end of the two wires (12) is connected to the secondary conductive block (13). The support shell (5) is provided with a delay buffer component (6) to delay and buffer the current during a short-term overcurrent, so as to avoid directly interrupting the measurement process; The delay buffer component (6) includes a conductive core (601), and the upper and lower surfaces of the conductive core (601) slide against the sides of the two secondary conductive blocks (13) respectively. The main conductive block (14) is electrically connected to the body (2). A hydraulic cylinder (602) is fixedly connected to the outer wall of the conductive core (601) facing the electromagnet (9), and a hydraulic rod (603) is slidably connected to the inner wall of the hydraulic cylinder (602). Hydraulic chambers (605) are symmetrically opened on the inner wall of the hydraulic cylinder (602). A piston (604) is fixedly connected to the end of the hydraulic rod (603) away from the electromagnet (9). A flow hole (606) is opened through the inner wall of the hydraulic chamber (605). A magnetic disk (607) is fixedly connected to the end of the hydraulic rod (603) facing the electromagnet (9). A tension spring (608) is fixedly connected to the end face of the magnetic disk (607) away from the electromagnet (9). The other end of the tension spring (608) is fixedly connected to the end of the hydraulic cylinder (602) facing the electromagnet (9). The outer wall of the support shell (5) is provided with an overcurrent cutoff component (7) to quickly separate when encountering a high overcurrent, so as to avoid direct breakdown by a large current. The overcurrent cutoff component (7) includes a magnetic ring (701), and connecting plates (702) are symmetrically fixedly connected to the outer walls of both sides of the magnetic ring (701). Each of the two connecting plates (702) has a limiting groove (703) inside, and a slider (704) is slidably connected to the inner wall of the limiting groove (703). A sliding rod (705) is fixedly connected to the outer wall of the slider (704) away from the electromagnet (9). A second spring (706) is fixedly connected to the outer wall of the two sliders (704) away from each other. One end of the two second springs (706) away from each other is fixedly connected to the inner wall of the limiting groove (703). A blocking block (707) is slidably connected to the outer wall of each of the two sliding rods (705). The outer walls of the support shell (5) are correspondingly blocked. A limiting groove (708) is opened through the block (707). The end of the slide rod (705) away from the electromagnet (9) is fixedly connected to the slide plate (709). The outer walls of the two sides of the support shell (5) are symmetrically connected to the slide plate (709) with guide blocks (710). The outer wall of the guide block (710) facing the slide plate (709) is inclined. The inner wall of the magnetic ring (701) is symmetrically provided with grooves (711). The inner wall of the groove (711) is fixedly connected to the spring three (712). The other end of the spring three (712) is fixedly connected to the locking block (713). The outer wall of the magnetic disk (607) is provided with a locking groove (714) corresponding to the locking block (713). The end of the locking block (713) facing the locking groove (714) is frustum-shaped. The mounting box (4) is equipped with a release jamming component (8) to enable rapid physical isolation after power failure. The release jamming component (8) includes a locking rod (801), and the outer wall of the locking rod (801) is slidably connected to the inner wall of the mounting box (4). The end of the locking rod (801) facing the conductive core (601) is inclined.

2. The automatic power-off device for a digital voltmeter according to claim 1, characterized in that, It also includes a wire (10) and an input electrode plate (11). The two input electrode plates (11) are respectively installed on the upper and lower surfaces of the mounting box (4). The two ends of the wire (10) are respectively connected to the two input electrode plates (11). The wire (10) and the electromagnet (9) are connected in series.

3. The automatic power-off device for a digital voltmeter according to claim 2, characterized in that, The outer wall of the piston (604) slides and matches the inner wall of the hydraulic chamber (605).

4. The automatic power-off device for a digital voltmeter according to claim 3, characterized in that, The outer wall of the blocking block (707) slides in contact with the inner wall of the limiting groove (708).

5. The automatic power-off device for a digital voltmeter according to claim 4, characterized in that, The outer walls of the two sliding plates (709) that are close to each other slide against the outer walls of the two sides of the support shell (5).

6. The automatic power-off device for a digital voltmeter according to claim 5, characterized in that, The outer wall of the card block (713) slides against the inner wall of the groove (711), and the card block (713) forms a telescopic structure with the groove (711) through the spring three (712).

7. The automatic power-off device for a digital voltmeter according to claim 6, characterized in that, The support shell (5) has an adsorption cavity (715) through it on the side facing the electromagnet (9). The outer wall of the magnetic ring (701) slides against the inner wall of the adsorption cavity (715). The support shell (5) has symmetrical grooves (716) on the side facing the electromagnet (9). The outer wall of the connecting plate (702) slides against the inner wall of the groove (716). A reset frame (15) is slidably installed on the top of the support shell (5). A spring (16) is fixedly connected to the bottom of the reset frame (15). The bottom of the spring (16) is fixedly connected to the top of the mounting box (4). The two ends of the bottom of the reset frame (15) are inclined to the connecting plate (702).

8. The automatic power-off device for a digital voltmeter according to claim 7, characterized in that, A second tension spring (802) is fitted to the outer wall of the locking rod (801), and a mounting plate (803) is fixedly connected to the outer wall of the locking rod (801). One end of the second tension spring (802) is fixedly connected to one side wall of the mounting plate (803), and the other end of the second tension spring (802) is fixedly connected to one side outer wall of the support shell (5). A reset plate (804) is fixedly connected to the other end of the locking rod (801).

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