An alloy type thermal fuse with a metal cover plate

Abstract

The application provides an alloy thermal fuse with a metal cover. The thermal fuse is provided with a center cavity or a special-shaped center cavity in the middle of a shell, right and left end sealing cavities are arranged at the two ends of the shell respectively, a cover is arranged at the two ends or one end of the center cavity or the special-shaped center cavity, the two ends of a thermal element are welded with lead wires respectively, the outer surface of the thermal element is wrapped with a flux, the lead wires extend to the outside of the shell through lead wire holes in the cover, and the right and left end sealing cavities are sealed by epoxy resin glue. The lead wire is flattened by beating or stamping one end of the lead wire before being welded with the thermal element. The thermal fuse is provided with a metal cover between the thermal element and the epoxy resin glue, the metal cover is used to prevent the high-temperature flame formed by the thermal element of the thermal fuse at the moment of fusing from directly burning the epoxy resin glue by using the rapid heat absorption performance of the metal cover.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of thermal cutout, in particular to an alloy type thermal cutout with a metal cover plate. BACKGROUND

[0002] At present, when the existing high-power household heating appliances are used, the household heating appliances will quickly heat up under abnormal circuit conditions, and when the abnormal temperature rise of the heating appliance reaches a certain value, it will affect the normal work of the entire high-power household heating appliance, and in severe cases, it will cause the high-power household heating appliance to catch fire and burn. The working principle of the thermal cutout is that the thermal energy of the household heating appliance is transmitted to the shell of the thermal cutout, and the shell transmits the thermal energy to the thermal element and flux through epoxy resin glue and lead wires, and the thermal element is melted under the action of the flux, thereby breaking the power supply circuit and protecting the household heating appliance from accidents or fire. The temperature protection alloy type thermal cutout used in the prior art will form an electric arc between the two lead wires in the shell when the temperature sensing thermal element is melted under high temperature and large current, which will directly act on the epoxy resin glue at the opening of the shell, causing the performance of the epoxy resin glue to drop instantaneously. When the adhesion between the epoxy resin glue and the lead wire decreases, the molten liquid thermal element material and the molten flux will overflow along the joint surface of the lead wire and the epoxy resin glue, resulting in no guarantee of the electrical safety of the entire thermal cutout.

[0003] The invention patent with the patent number 201210096329.3 and the patent name temperature fuse, its main technical features are: a fusible part: a first lead conductor and a second lead conductor, which respectively extend from two ends of the fusible part; a first step part and a second step part, the first step part is formed on the first lead conductor, and the second step part is formed on the second lead conductor; a cylindrical shell, which is inserted into the fusible part, the first lead conductor and the second lead conductor from an opening at one end thereof, and accommodates the fusible part in a state that the end portions of the first lead conductor and the second lead conductor are led out to the outside; a convex part: which is formed on the inner surface near the other end of the shell, used for clamping the first lead conductor side; and a cover, which is sleeved on the second lead conductor and clamped by the second step part. SUMMARY

[0004] The present application aims to provide an alloy type thermal cutout with a metal cover plate. The technical problem to be solved by the present application is to prevent the electric arc formed when the thermal cutout is melted under high temperature and large current from instantaneously burning the epoxy resin glue in the shell, and to prevent the molten liquid thermal element material from overflowing from the thermal cutout; greatly improve the product qualification rate of the thermal cutout during batch production, so that 100% of the batch-produced thermal cutouts meet the current national standard for thermal cutouts.

[0005] The design idea of the present application is: 1, increase the metal cover plate between the thermal element and the epoxy resin glue, use the rapid heat absorption performance of the metal cover plate to prevent the high temperature flame formed by the thermal element of the thermal fuse in the moment of melting from directly burning the epoxy resin glue; 2, use the rapid heat conduction performance of the metal cover plate to absorb part of the heat energy released by the thermal element of the thermal fuse in the moment of melting due to arc discharge, prevent the temperature in the shell of the thermal fuse from rising rapidly, and protect the thermal fuse from being damaged by the high pressure formed by the gas expansion in the shell; 3, the material of the metal cover plate is selected from metal materials which are convenient for stamping and have good heat conductivity, such as copper sheet, silver sheet, etc., and the effect is better if the copper sheet is plated with tin, silver, etc., at the same time, by using the mutual melting property of the tin layer plated on the surface of the metal cover plate and the tin contained in the thermal element of the thermal fuse, the small thermal element liquid particles splashed due to arc discharge when the thermal fuse melts can be adsorbed on the surface of the metal cover plate, reducing the risk of the splashed small thermal element liquid particles participating in the conductive arc again, and protecting the thermal fuse from being damaged by continuous arc discharge; 4, according to the size of the current in the circuit where the thermal fuse product is used, the thickness of the metal cover plate is controlled to prevent the metal cover plate from rising too high in temperature after absorbing the heat energy of the arc discharge due to insufficient heat capacity, thereby failing to effectively slow down the rapid rise of the temperature of the epoxy resin glue; 5, the shape of the metal cover plate can be made into a circular shape, a square shape, etc., or a multi-claw shape such as an eight-claw shape, and the eight-claw shape has better operation and use effect; 6, the installation direction of the metal cover plate can be designed to be installed from both sides of the shell to the center position of the shell, or can be designed to be installed from the right side of the shell; 7, the structure of the shell can be designed to use two metal cover plates at the same time, or can be designed to use the metal cover plate on one side and the material of the shell itself on the other side for protection; 8, the material of the shell is preferably 95 ceramic, or plastic with good heat conduction, insulation and temperature resistance, and the shape of the shell is circular or square; 9, at the position close to the thermal element at the front end of the two leads, the leads are struck or stamped into a flat shape to prevent the thermal element from having inconsistent melting performance due to direct contact with the thermal element, and at the same time, the thermal element can be ensured to always be located at the center position in the shell.

[0006] To achieve the above object, the technical scheme of the present application is:

[0007] An alloy type thermal fuse with a metal cover plate comprises a shell, leads, a thermal element, a flux, a cover plate, epoxy resin glue, a center cavity, a right end sealing cavity, a lead hole, a through hole, a left end sealing cavity and a special-shaped center cavity, the thermal fuse is provided with a center cavity or a special-shaped center cavity in the middle of the shell, the two ends of the shell are respectively provided with a right end sealing cavity and a left end sealing cavity, the cover plate is arranged at the two ends or one end of the center cavity or the special-shaped center cavity, the two ends of the thermal element are respectively welded with the leads, the outer surface of the thermal element is wrapped with the flux, the leads extend to the outside of the shell through the lead hole in the cover plate, and the right end sealing cavity and the left end sealing cavity are sealed with the epoxy resin glue.

[0008] The lead wire in the thermal fuse is flattened at one end before being welded with the thermal element.

[0009] The shell of the thermal fuse is circular or rectangular, the center cavity or the special-shaped center cavity arranged in the shell is circular or rectangular, the inner diameter of the center cavity or the special-shaped center cavity is smaller than the inner diameter of the right end sealing cavity and not larger than the inner diameter of the left end sealing cavity, and the hole diameter of the through hole is smaller than the inner diameter of the left end sealing cavity, so that the two ends of the center cavity or the special-shaped center cavity form bosses.

[0010] The center of the cover plate of the thermal fuse is provided with a lead wire hole, which is in any one of circular, square, octopus-shaped or multi-claw-shaped, the thickness of the cover plate varies with the characteristics of the thermal fuse, and the cover plate is made of a metal material which is convenient for punching forming and has good thermal conductivity.

[0011] One end of the special-shaped center cavity arranged in the shell of the thermal fuse is provided with a through hole, and the lead wire extends to the outside of the shell through the through hole.

[0012] The size, shape and thickness of the cover plate in the thermal fuse vary with the shape of the shell, and the cover plate is installed from the left and right ends of the shell or sequentially installed from the right end of the shell.

[0013] Compared with the prior art, the beneficial effects of the present application are:

[0014] 1. The thermal fuse increases a metal cover plate between the thermal element and the epoxy resin glue, uses the rapid heat absorption performance of the metal cover plate to prevent the high-temperature flame formed by the thermal element of the thermal fuse at the moment of fusing from directly burning the epoxy resin glue;

[0015] 2. The thermal fuse uses the rapid heat conduction performance of the metal cover plate to absorb part of the heat energy released by the thermal element of the thermal fuse at the moment of fusing due to arc drawing, prevents the temperature in the shell of the thermal fuse from rapidly rising at the moment, and protects the thermal fuse from being damaged by high pressure formed by the expansion of gas in the shell;

[0016] 3. The metal cover plate of the thermal fuse is made of a metal material which is convenient for punching forming and has good thermal conductivity, such as copper sheet, silver sheet, etc., and the effect is better when the copper sheet is plated with tin or silver;

[0017] 4. The thickness of the metal cover plate of the thermal fuse is controlled according to the size of the current in the circuit where the thermal fuse product is used, so as to prevent the temperature from rising too high after absorbing the heat energy of arc drawing due to insufficient heat capacity of the metal cover plate, thereby not being able to effectively slow down the rapid rise of the temperature of the epoxy resin glue;

[0018] 5. The shape of the metal cover plate of the thermal fuse can be made into circular, square, octopus-shaped or multi-claw-shaped, and the operation and use effect of the octopus-shaped cover plate are better.

[0019] 6. The installation direction of the metal cover plate can be designed to be installed from both the left and right sides of the housing towards the center of the housing simultaneously, or it can be designed to be installed from the right side of the housing.

[0020] 7. The shell structure of the thermal fuse can be designed to use two metal cover plates at the same time, or it can be designed to use a metal cover plate on the right side and use the shell material itself for protection on the left side.

[0021] 8. The fuses produced using this structure meet 100% of the current national standards for fuses, ensuring that the fuses produced in batches are 100% qualified. Attached Figure Description

[0022] Figure 1 A schematic diagram of the main structure of a thermocouple with bimetallic cover plates installed on both sides;

[0023] Figure 2 A top-section view of the shell structure of the thermosetting fuselage with bimetallic cover plates installed on both sides;

[0024] Figure 3 Schematic diagram of the left view of the circular shell structure of the bimetallic cover plate heat-fused fuse;

[0025] Figure 4 Schematic diagram of the left view of the square shell structure of the bimetallic cover plate heat-fused fuse;

[0026] Figure 5 Schematic diagram of the main structure of a circular metal cover plate with a heat-fused fuse;

[0027] Figure 6 A schematic diagram of the left cross-sectional structure of a circular metal cover plate with a heat-fused fracture structure;

[0028] Figure 7 Schematic diagram of the main structure of the octagonal metal cover plate with heat-fused fuse;

[0029] Figure 8 A schematic diagram of the left cross-sectional structure of the octagonal metal cover plate with a heat-fused fracture structure;

[0030] Figure 9 Schematic diagram of the main structure of the five-claw-shaped metal cover plate with heat-fused fuse;

[0031] Figure 10 Schematic diagram of lead wires, heating elements and flux structure;

[0032] Figure 11 Schematic diagram of the main cross-sectional structure of the fusible link with the bimetallic cover plate installed on the right side;

[0033] Figure 12 Schematic diagram of the top section of the fuselage shell with the bimetallic cover plate installed on the right side;

[0034] Figure 13 , the schematic diagram of the main section structure of the thermal fuse with single metal cover plate;

[0035] Figure 14 , the schematic diagram of the shell section structure of the thermal fuse with single metal cover plate.

[0036] In the figure: 1, shell, 2, lead wire, 3, thermal element, 4, flux, 5, cover plate, 6, epoxy resin glue, 7, center cavity, 8, right end sealing cavity, 9, lead wire hole, 10, through hole, 11, left end sealing cavity, 12, special-shaped center cavity. DETAILED DESCRIPTION

[0037] The technical solutions of the present application are further described below in combination with the drawings and examples.

[0038] Referring to the drawings Figure 1 14, the thermal fuse is provided with a center cavity 7 or a special-shaped center cavity 12 in the middle of the shell 1, the shell 1 is provided with a right end sealing cavity 8 and a left end sealing cavity 11 at both ends respectively, the cover plate 5 is installed at both ends or one end of the center cavity 7 or the special-shaped center cavity 12, the both ends of the thermal element 3 are welded with the lead wire respectively, the outer surface of the thermal element 3 is wrapped with the flux 4, the lead wire 2 extends to the outside of the shell 1 through the lead wire hole 9 in the cover plate 5, and the right end sealing cavity 8 and the left end sealing cavity 11 are sealed with the epoxy resin glue 6.

[0039] Before being welded with the thermal element 3, one end of the lead wire 2 in the thermal fuse is hit or stamped into a flat shape, and then is welded with the thermal element 3.

[0040] The shell 1 of the thermal fuse is circular or rectangular in shape, the center cavity 7 or the special-shaped center cavity 12 provided in the shell 1 is circular or rectangular in shape, the inner diameter of which is smaller than that of the right end sealing cavity 8 and not larger than that of the left end sealing cavity 11, and the hole diameter of the through hole 10 is smaller than the inner diameter of the left end sealing cavity 11, so that the both ends of the center cavity 7 or the special-shaped center cavity 12 form a boss.

[0041] The cover plate 5 of the thermal fuse is provided with a lead wire hole 9 in the center, which is circular, octopus-shaped or any one of multi-claw-shaped, the thickness of the cover plate 5 varies according to the characteristics required by the thermal fuse, and the cover plate 5 is made of metal material which is easy to be stamped and formed and has good thermal conductivity.

[0042] The special-shaped center cavity 12 provided in the shell 1 of the thermal fuse is provided with a through hole 10 at one end, the lead wire (2) extends to the outside of the shell 1 through the through hole 10, and the special-shaped center cavity 12 can be circular, square, etc.

[0043] The size, shape and thickness of the cover plate 5 in the thermal fuse vary according to the shape of the shell 1, and the cover plate 5 is installed from both ends of the shell 1 or sequentially from the right end of the shell 1.

[0044] Example 1

[0045] The bimetallic cover is installed from both ends of the housing:

[0046] Before assembling the fusible link, different types of molds are selected according to the environment and installation dimensions of the fusible link. A central cavity 7 is stamped out inside the housing 1, and a right-end sealing cavity 8 and a left-end sealing cavity 11 are stamped out at both ends of the housing 1. The inner diameters of the right-end sealing cavity 8 and the left-end sealing cavity 11 are larger than the inner diameter of the central cavity 7, forming bosses at both ends of the central cavity 7. Before welding the two leads 2 to the heating element 3, one end of the two leads 2 is struck or stamped into a flat shape, and then welded to the heating element 3. After welding, flux 4 is applied to the outside of the heating element 3. The heating element 3 coated with flux 4 and the leads 2 are fed into the central cavity 7 through the right-end sealing cavity 8, and the other end of the leads 2 passes out from the left-end sealing cavity 11. Two cover plates 5 are respectively fitted onto the bosses at both ends of the central cavity 7 from the left and right leads 2 to prevent the heating element 3 installed in the central cavity 7 from moving. Finally, the prepared epoxy resin adhesive 6 is injected into the right end sealing cavity 8 and the left end sealing cavity 11 at both ends of the housing 1 to seal the installed lead wire 2.

[0047] When a circuit malfunction causes a rapid rise in the surface temperature of the heating plate, the temperature of the thermal fuse, which is in direct contact with the outer surface of the heating plate, also rises. It transfers the absorbed heat to the heating element 3. When the temperature of the heating element 3 reaches its rated operating temperature, it melts rapidly with the help of the molten flux 4. The housing 1 utilizes the rapid heat absorption properties of its metal cover 5 to prevent the high-temperature flame generated by the thermal fuse 3 at the moment of melting from directly burning the epoxy resin adhesive 6. This avoids the situation where the epoxy resin adhesive 6, after being burned by the high-temperature flame, cannot prevent the molten heating element 3 from overflowing along the leads, thus achieving the purpose of circuit safety protection.

[0048] Example 2

[0049] The bimetallic cover is installed from the right end of the housing:

[0050] Before assembling the thermal fuse, different types of molds are selected according to the environment and installation dimensions of the thermal fuse. A shaped central cavity 12 is stamped out inside the housing 1. Then, a right end sealing cavity 8 is stamped out at the right end of the housing 1, and a left end sealing cavity 11 is stamped out at the left end. The inner diameter of the right end sealing cavity 8 is larger than the inner diameter of the shaped central cavity 12, and the inner diameter of the left end sealing cavity 11 is larger than the diameter of the through hole 10. The diameter of the through hole 10 is smaller than the inner diameter of the shaped central cavity 12. Bosses are formed at both ends of the shaped central cavity 12. Before welding the two leads 2 to the heating element 3, one end of each lead 2 is struck or stamped into a flat shape before welding to the heating element 3. Then, flux 4 is applied to the outside of the welded heating element 3. Two cover plates 5 are inserted onto both sides of the heating element 3 from the left and right leads 2 respectively. Finally, the heat element 3 coated with flux 4, the leads 2, and the cover plates 5 are fed into the irregularly shaped central cavity 12 through the right-end sealing cavity 8. The two cover plates 5 are installed on the boss, and the other end of the leads 2 passes through the left-end sealing cavity 11. This prevents the heating element 3 inside the irregularly shaped central cavity 12 from moving. Finally, prepared epoxy resin 6 is injected into the right-end sealing cavity 8 and the left-end sealing cavity 11 at both ends of the housing 1 to seal the installed leads 2.

[0051] When a circuit malfunction causes a rapid rise in the surface temperature of the heating plate, the temperature of the thermal fuse, which is in direct contact with the outer surface of the heating plate, also rises. It transfers the absorbed heat to the heating element 3. When the temperature of the heating element 3 reaches its rated operating temperature, it melts rapidly with the help of the molten flux 4. The housing 1 utilizes the rapid heat absorption properties of its metal cover 5 to prevent the high-temperature flame generated by the thermal fuse 3 at the moment of melting from directly burning the epoxy resin adhesive 6. This avoids the situation where the epoxy resin adhesive 6, after being burned by the high-temperature flame, cannot prevent the molten heating element 3 from overflowing along the leads, thus achieving the purpose of circuit safety protection.

[0052] Example 3

[0053] Single metal cover installation status:

[0054] Before assembling the thermal fuse, different types of molds are selected according to the environment and installation dimensions of the thermal fuse. A shaped central cavity 12 is stamped out inside the housing 1. A right-end sealing cavity 8 is stamped out at the right end of the housing 1, and a left-end sealing cavity 11 is stamped out at the left end. The inner diameter of the right-end sealing cavity 8 is larger than the inner diameter of the shaped central cavity 12, and the inner diameter of the left-end sealing cavity 11 is larger than the diameter of the through hole 10. The diameter of the through hole 10 is smaller than the inner diameter of the shaped central cavity 12. Bosses are formed at both ends of the shaped central cavity 12, and a through hole 10 is opened at the left end of the shaped central cavity 12. Before welding the two leads 2 to the heating element 3, one end of each lead 2 is struck or stamped into a flat shape before welding to the heating element 3. Then, flux 4 is applied to the outside of the welded heating element 3. The flux-coated heating element 3 is then fed into the irregularly shaped central cavity 12 through the right-end sealing cavity 8. The other end of the lead 2 passes through the through hole 10 from the left-end sealing cavity 11. A cover plate 5 is installed from the right end of the housing 1 along the lead 2 through the right-end sealing cavity 8 on the boss at the right end of the irregularly shaped central cavity 12, preventing the heating element 3 inside the irregularly shaped central cavity 12 from moving. Finally, prepared epoxy resin 6 is injected into the right-end sealing cavities 8 and left-end sealing cavities 11 at both ends of the housing 1 to seal the installed lead 2.

[0055] When a circuit malfunction causes a rapid rise in the surface temperature of the heating plate, the temperature of the thermal fuse, which is in direct contact with the outer surface of the heating plate, also rises. It then conducts the absorbed heat to the heating element 3. Once the temperature of the heating element 3 reaches its rated operating temperature, it melts rapidly with the help of the molten flux 4. The housing 1 utilizes the rapid heat absorption properties of the metal cover 5 and the protrusion at the left end of the irregularly shaped central cavity 12 to prevent the high-temperature flame generated by the heating element 3 at the moment of melting from directly burning the epoxy resin adhesive 6. This avoids the situation where the epoxy resin adhesive 6 is burned by the high-temperature flame, preventing the melted heating element 3 from overflowing along the leads, thus achieving the purpose of circuit safety protection.

[0056] Instance detection results

[0057] Experiment 1:

[0058] Product model: 130℃, 250V, 2A; Quantity of test products: 50 pieces;

[0059] Test conditions: Test voltage: AC 275V, test current: AC 3A, voltage frequency: 50Hz.

[0060] Test results: 1. The actual melting temperature of the product is 127±0.3℃.

[0061] 2. Visually inspect the product for completeness, no damage, no loose leads, and no leakage of heating elements or flux from the casing.

[0062] Experiment 2:

[0063] Product model: 140℃, 250V, 2A; Quantity of test products: 50 pieces;

[0064] Test conditions: Test voltage: AC 275V, test current: AC 3A, voltage frequency: 50Hz.

[0065] Test results: 1. The actual melting temperature of the product is 135±0.3℃.

[0066] 2. Visually inspect the product for completeness, no damage, no loose leads, and no leakage of heating elements or flux from the casing.

[0067] Experiment 3:

[0068] Product Model: 125℃, 250V, 2A; Quantity of Test Products: 50 pieces

[0069] Test conditions: Test voltage: AC 275V, test current: AC 3A, voltage frequency: 50Hz.

[0070] Test results: 1. The actual melting temperature of the product is 121±0.3℃.

[0071] 2. Visually inspect the product for completeness, no damage, no loose leads, and no leakage of heating elements or flux from the casing.

[0072] The above three sets of test data show that adding a metal cover plate inside the housing of the alloy-type thermal fuse can effectively prevent the molten thermal element from overflowing outward along the bonding position between the epoxy resin and the lead wire. It can effectively reduce the gas pressure inside the housing at the moment the thermal element melts and prevent the housing from breaking, thus achieving safe and leak-free melting of the thermal fuse and better protecting the electrical safety of household appliances.

[0073] All features disclosed in this specification, or combinations, connections, and assemblies of all disclosed components, except for mutually exclusive features and / or steps, can be combined in any manner covered by the technical solutions of this invention. Any feature disclosed in this specification (including the claims and abstract), unless specifically stated otherwise, can be replaced by other equivalent or similar features. That is, unless specifically stated otherwise, each feature is merely one example of a series of equivalent or similar features.

[0074] The above description is only a non-limiting embodiment of the present invention, and a large number of embodiments can be derived. For those skilled in the art, without departing from the inventive concept of the present invention and without creative effort, several modified and improved embodiments can be made, all of which fall within the protection scope of the present invention.

Claims

1. An alloy fusible link with a metal cover plate comprising: The shell (1), lead wire (2), thermal element (3), fluxing agent (4), cover plate (5), epoxy resin glue (6), right end sealing cavity (8), lead wire hole (9), through hole (10), left end sealing cavity (11) and special-shaped center cavity (12), characterized in that: the thermal fuse is provided with a special-shaped center cavity (12) in the middle of the shell (1), the two ends of the shell (1) are provided with a right end sealing cavity (8) and a left end sealing cavity (11) respectively, cover plates (5) are installed at the two ends of the special-shaped center cavity (12), the cover plates (5) are made of copper sheet which is easy to be punched and has good thermal conductivity, and the copper sheet is tinned, the thermal element (3) contains tin, the cover plates (5) at the two ends of the special-shaped center cavity (12) form a rapid heat absorption area; the special-shaped center cavity (12) is circular or rectangular, the inner diameter of the special-shaped center cavity (12) is smaller than that of the right end sealing cavity (8) and not greater than that of the left end sealing cavity (11), a through hole (10) is formed at the left end of the special-shaped center cavity (12) and the diameter of the through hole (10) is smaller than the inner diameter of the left end sealing cavity (11), so that bosses are formed at the two ends of the special-shaped center cavity (12), and the cover plates (5) at the two ends of the special-shaped center cavity (12) are installed on the bosses; the two ends of the thermal element (3) are welded with the lead wires (2) respectively, the outer surface of the thermal element (3) is wrapped with the fluxing agent (4), the lead wire (2) at one end of the thermal element (3) extends to the outside of the shell (1) through the lead wire hole (9) in the cover plate (5), and the lead wire (2) at the other end of the thermal element (3) extends to the outside of the shell (1) through the lead wire hole (9) in the cover plate (5) and the through hole (10), and the right end sealing cavity (8) and the left end sealing cavity (11) are sealed with the epoxy resin glue (6). In use, when the circuit abnormally causes the surface temperature of the heating plate to rapidly rise, the temperature of the thermal fuse directly contacting the outer surface of the heating plate also rises, the thermal fuse absorbs the heat energy and conducts it to the thermal element (3), when the temperature of the thermal element (3) rises to the rated action temperature, the thermal element (3) is quickly fused under the help of the already melted fluxing agent (4); Before the lead wire (2) in the thermal fuse is welded with the thermal element (3), one end of the lead wire (2) is struck or punched into a flat shape, and then the lead wire (2) is welded with the thermal element (3); the size, shape and thickness of the cover plate (5) in the thermal fuse change with the shape of the shell (1), and the cover plate (5) is installed from the right end of the shell (1) in sequence.

2. The alloy fusible link with metal cover plate of claim 1 wherein: The shell (1) of the thermal fuse is circular or rectangular in shape.

3. The alloy fusible link with metal cover plate of claim 1 wherein: The cover plate (5) of the thermal fuse is provided with a lead wire hole (9) in the center, and the shape of the lead wire hole (9) is any one of circular, eight-claw or multi-claw.

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