Pointer type ammeter with overload protection device

Abstract

The utility model discloses a pointer type ammeter with an overload protection device, and belongs to the technical field of electrical instruments. A pointer type ammeter with an overload protection device comprises a housing, a dial, a rotating shaft and a pointer, the dial is provided with a circular hole, the rotating shaft penetrates through the circular hole, the pointer is connected with the rotating shaft, the pointer is located above the dial, the pointer type ammeter also comprises a hairspring arranged on one side of the rotating shaft, one end of the hairspring is fixed on the dial, and the other end of the hairspring is fixed on the housing. And the other end of the hairspring is opposite to the pointer. The pointer type ampere meter with the overload protection device can protect itself when overload occurs in the current transmission process.

Description

Technical Field

[0001] The utility model relates to the technical field of electrical instruments, in particular to a pointer-type ammeter with an overload protection device. Background Art

[0002] An ammeter is an instrument used to measure the current in AC and DC circuits. A pointer ammeter is an ammeter that uses the principle of magnetoelectricity to drive the pointer to move, and displays the degree of the current by the position of the pointer on the panel. There is a permanent magnet inside the pointer ammeter, which generates a magnetic field between the poles. There is a coil in the magnetic field, and there is a hairspring at each end of the coil. The hairspring is connected to a terminal of the ammeter. The hairspring and the coil are connected by a rotating shaft. There is a pointer at the front end of the rotating shaft relative to the ammeter. When current passes through, the current passes through the magnetic field along the hairspring and the rotating shaft, and the current cuts the magnetic flux lines. Therefore, under the action of the magnetic field force, the coil is deflected, driving the rotating shaft and the pointer to deflect. Moreover, the magnitude of the magnetic field force increases with the increase of current and decreases with the decrease of current, so the magnitude of the current can be observed by the degree of deflection of the pointer. Pointer ammeters are widely used due to their simple structure.

[0003] Since the pointer-type ammeter uses a mechanical pointer structure to indicate the magnitude of the current, improper range selection and serious over-tolerance may occur during use, resulting in excessive deflection of the pointer and hitting the inner wall of the shell, causing the pointer to bend and deviate from the zero position and unable to return to zero. For this reason, overload protection measures are generally installed on the ammeter to deal with the overload of the measured current. However, the overload protection measures for pointer-type ammeters in the prior art are implemented by protection circuits, which not only increases the difficulty and volume of the ammeter, but also once a calculation error or underestimation occurs, the pointer of the ammeter in use will be bent due to the failure to provide a hardware protection measure in a timely manner, affecting the normal use function. Summary of the invention

[0004] The purpose of the utility model is to solve the problem that in the prior art, the overload protection measure of the pointer type ammeter is realized by the protection circuit. Once a calculation error or insufficient estimation occurs, the pointer in use may be bent due to the failure to provide a hardware protection measure in time. A pointer type ammeter with an overload protection device is proposed.

[0005] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0006] A pointer type ammeter with an overload protection device comprises a housing, a dial, a rotating shaft and a pointer, wherein the dial is provided with a round hole, the rotating shaft is passed through the round hole, the pointer is connected to the rotating shaft, the pointer is located above the dial, and further comprises a hairspring arranged on one side of the rotating shaft, one end of the hairspring is fixed on the dial, and the other end of the hairspring is arranged opposite to the pointer.

[0007] In some embodiments, a column is provided on the dial, and the hairspring includes an end 1 and an end 2, wherein the end 1 is connected to the column, and the end 1 and the end 2 are connected via a curved portion, and the curved portion is an arc-shaped structure.

[0008] In some embodiments, the pointer includes an annular portion and a straight portion integrally provided on the outer circumference of the annular portion, the annular portion is sleeved on the rotating shaft, a waist is provided at one end of the straight portion close to the annular portion, and the other end of the straight portion is connected to an inclined portion.

[0009] In some embodiments, the waist is a U-shaped structure, and the waist is arranged opposite to the second end of the hairspring.

[0010] In some embodiments, the distance between the inclined portion and the scale plate gradually decreases in a direction away from the straight portion, and a tip is provided at the end of the inclined portion.

[0011] In some embodiments, a slot is provided at one end of the column, and the end of the hairspring is clamped in the slot, and the other end of the column is connected to the dial through a thread.

[0012] In some embodiments, the housing is connected to the dial via screws.

[0013] Compared with the prior art, the utility model provides a pointer-type ammeter with an overload protection device, which has the following beneficial effects.

[0014] When the utility model is used, when the measured current is within the maximum range of the pointer-type ammeter, the hairspring does not contact the pointer, and when the measured current exceeds the maximum range of the pointer-type ammeter, the magnetic field force generated by the overload is transmitted to the pointer through the rotating shaft, and then the waist of the pointer begins to contact and compress the second end of the hairspring, and the above-mentioned magnetic field force is converted into the force formed by the pointer on the second hairspring. At this time, the compressed hairspring generates a reaction force on the pointer through its own elastic force to balance the magnetic field force generated by the overload and prevent the pointer from being excessively deflected and hitting the inner wall of the shell. In addition, by adding a hairspring, compared with the measures implemented by the protection circuit in the prior art, the structure is simple and practical, and the cost is also relatively low.

[0015] The parts not involved in the device are the same as the prior art or can be implemented by using the prior art. The utility model uses the reaction force generated by the hairspring to balance the magnetic field force generated by the overload of the measured current to prevent the pointer from being bent.

[0016] Other advantages, objectives and features of the present invention will be described in the following description to some extent; and will be apparent to those skilled in the art based on the following examination and study to some extent; or, may be taught from the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a stereogram of the utility model.

[0018] Figure 2 It is a schematic diagram of the dial of the utility model, and the shell is not shown in the figure.

[0019] Figure 3 It is a schematic diagram of a pointer of the utility model.

[0020] Figure 4 It is a schematic diagram of the hairspring and the column of the utility model.

[0021] Figure 5 It is a schematic diagram of the contact state between the hairspring and the pointer of the utility model.

[0022] The reference numerals in the accompanying drawings are:

[0023] 1. Housing; 2. Dial; 3. Rotating shaft; 4. Pointer; 401. Ring part; 402. Straight part; 403. Waist; 404. Inclined part; 405. Tip; 5. Hairspring; 501. End one; 502. End two; 503. Bend part; 6. Column; 7. Slot; 8. Screw. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0025] Reference Figure 1-Figure 5 A pointer ammeter with an overload protection device includes a housing 1, a dial 2, a rotating shaft 3 and a pointer 4. The dial 2 is provided with a round hole, the rotating shaft 3 is passed through the round hole, the pointer 4 is connected to the rotating shaft 3, and the pointer 4 is located above the dial 2. It also includes a hairspring 5 arranged on one side of the rotating shaft 3, one end of the hairspring 5 is fixed on the dial 2, and the other end of the hairspring 5 is arranged opposite to the pointer 4.

[0026] Specifically, a column 6 is provided on the dial 2, and the hairspring 5 includes an end 1 501 and an end 2 502, wherein the end 1 501 is connected to the column 6, and the end 1 501 and the end 2 502 are connected via a bending portion 503, wherein the bending portion 503 is an arc-shaped structure and generates elastic force when the bending portion 503 is compressed and deformed.

[0027] Please refer again Figure 3The pointer 4 includes an annular portion 401 and a straight portion 402 integrally arranged on the outer circumference of the annular portion 401, the annular portion 401 is mounted on the rotating shaft 3, a waist 403 is arranged at one end of the straight portion 402 close to the annular portion 401, and the other end of the straight portion 402 is connected to an inclined portion 404.

[0028] In this embodiment, the waist 403 is a U-shaped structure, and the waist 403 is arranged opposite to the second end 502 of the hairspring 5.

[0029] Furthermore, the distance between the inclined portion 404 and the scale plate 2 gradually decreases in the direction away from the straight portion 402, and a pointed portion 405 is provided at the end of the inclined portion 404, so that the indication is accurate.

[0030] In this embodiment, a slot 7 is provided at one end of the column 6, and the end 501 of the hairspring 5 is clamped in the slot 7. The other end of the column 6 is connected to the dial 2 through a thread; in addition, the housing 1 is connected to the dial 2 through a screw 8 for easy disassembly and assembly.

[0031] It is worth mentioning that the utility model uses the reaction force generated by the hairspring 5 to balance the magnetic field force generated by the overload of the measured current to prevent the pointer 4 from being bent. Moreover, by adding the hairspring 5, compared with the measures implemented by the protection circuit in the prior art, the structure is simple and practical. More importantly, it can perform effective hardware protection against overload conditions and is reliable to use.

[0032] The working principle of the utility model is:

[0033] Please refer again Figure 2 When the measured current is within the maximum range of the pointer ammeter, the hairspring 5 does not touch the pointer 4. When the measured current exceeds the maximum range of the pointer ammeter, please refer to Figure 5 , the pointer 4 continues to deflect to the right. At this time, the magnetic field force generated by the overload is transmitted to the pointer 4 through the rotating shaft 3. Then the waist 403 of the pointer 4 begins to contact and compress the second end 502 of the hairspring 5. The above-mentioned magnetic field force is converted into a force formed by the pointer 4 on the hairspring 5. At this time, the compressed hairspring 5 is bent and deformed to generate elastic force to form a reaction force on the pointer 4 to balance the magnetic field force generated by the overload and prevent the pointer 4 from deflecting excessively and hitting the inner wall of the housing 1; in summary, the pointer ammeter with an overload protection device provided by the utility model can protect itself when overloaded during the current transmission process, ensure that the pointer 4 will not be bent due to careless use, and ensure normal use function.

[0034] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes within the technical scope disclosed by the present invention according to the technical scheme and the utility model concept of the present invention, which should be covered by the protection scope of the present invention.

[0035] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0036] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations of the present invention. Ordinary technicians in the field can change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A pointer-type ammeter with an overload protection device, comprising a housing (1), a dial (2), a rotating shaft (3) and a pointer (4), wherein the dial (2) is provided with a circular hole, the rotating shaft (3) is inserted into the circular hole, the pointer (4) is connected to the rotating shaft (3), and the pointer (4) is located above the dial (2), characterized in that: It also includes a hairspring (5) arranged on one side of the rotating shaft (3), one end of the hairspring (5) is fixed on the scale plate (2), and the other end of the hairspring (5) is arranged opposite to the pointer (4).

2. A pointer type ammeter with an overload protection device according to claim 1, characterized in that: The dial (2) is provided with a column (6), the hairspring (5) comprises a first end (501) and a second end (502), the first end (501) is connected to the column (6), the first end (501) and the second end (502) are connected via a curved portion (503), and the curved portion (503) is an arc-shaped structure.

3. A pointer type ammeter with an overload protection device according to claim 2, characterized in that: The pointer (4) comprises an annular portion (401) and a straight portion (402) integrally arranged on the outer circumference of the annular portion (401); the annular portion (401) is sleeved on the rotating shaft (3); one end of the straight portion (402) close to the annular portion (401) is provided with a waist portion (403); and the other end of the straight portion (402) is connected to an inclined portion (404).

4. A pointer type ammeter with an overload protection device according to claim 3, characterized in that: The waist (403) is a U-shaped structure, and the waist (403) is arranged opposite to the second end (502) of the hairspring (5).

5. The pointer type ammeter with overload protection device according to claim 3, characterized in that: The distance between the inclined portion (404) and the scale plate (2) gradually decreases in a direction away from the straight portion (402), and a pointed portion (405) is provided at the end of the inclined portion (404).

6. A pointer type ammeter with an overload protection device according to claim 2, characterized in that: A slot (7) is formed at one end of the column (6), and an end (501) of the hairspring (5) is locked in the slot (7). The other end of the column (6) is connected to the scale plate (2) via a thread.

7. A pointer type ammeter with an overload protection device according to claim 1, characterized in that: The housing (1) is connected to the dial (2) via screws (8).

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