Thermal protector automatic welding machine

Abstract

The application discloses a kind of thermal protector automatic welding machine, it is related to thermal protector automatic welding technical field, for the welding surface of contact piece is welded to metal sheet, including base, movable mounting is equipped with lower electrode on base.Lower electrode includes several rectangular electrode blocks corresponding with the positioning slot adaptation, the top wall of rectangular electrode block is equipped with first resistance line, for the bottom wall of contact piece;The upper portion of base is provided with support table, movable mounting is equipped with upper electrode on support table, and upper electrode can be rolled relative to lower electrode;Upper electrode includes four fan-shaped electrode blocks that are evenly distributed in circumferential direction, and the outer ring wall of fan-shaped electrode block is equipped with second resistance line, for the top wall of metal sheet.The advantages are that: the present application is through automatic assembly line operation, cross staggered resistance line concentrated current and upper and lower electrode double wear compensation structure, realizes the efficient continuous welding of contact assembly, reliable promotion of welding quality and the substantial extension of electrode life, while reducing equipment and maintenance cost.

Description

Technical Field

[0001] This invention relates to the field of automatic welding technology for thermal protectors, and more particularly to an automatic welding machine for thermal protectors. Background Technology

[0002] Currently, in the field of thermal protector manufacturing, the welding of contact assemblies (i.e., the welding assembly of metal sheets and contact pieces) is generally carried out manually one by one or by relying on multi-station automatic welding machines.

[0003] First, manual welding relies on operators placing metal sheets and contact pieces manually and then spot welding them one by one. This method suffers from significant problems such as high labor intensity, low production efficiency, and welding quality being greatly affected by human factors, making it difficult to meet the needs of large-scale production. While multi-station automatic welding machines have improved automation to some extent, their complex structure, high manufacturing costs, and difficult maintenance make them unaffordable for small and medium-sized enterprises.

[0004] Secondly, both of the above methods use static spot welding process. The contact surface (i.e. working surface) of the electrode is usually a plane. The flat end face will wear down after long-term use, mainly manifested as an increase in the diameter of the end face (collapsed edge) or an uneven surface. This will result in uneven distribution of welding current and failure of pressure transmission, which seriously affects the stability of welding quality.

[0005] Furthermore, when the working surface of the electrode is worn, the traditional approach is to replace the entire electrode after it is worn to the point of being unusable. This not only results in high maintenance costs and long downtime, but also makes it difficult to maintain welding consistency in the production process over a long period due to the lack of online compensation methods.

[0006] Therefore, in order to improve welding continuity and welding stability, this invention provides an automatic welding machine for thermal protectors. Summary of the Invention

[0007] The purpose of this invention is to solve the problems existing in the prior art by proposing an automatic welding machine for thermal protectors.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: an automatic welding machine for thermal protectors, used to weld contact pieces to the welding surface of a metal sheet, comprising: a base, wherein a lower electrode is movably mounted on the base.

[0009] The top wall of the base is provided with several evenly distributed positioning grooves, which are used to accommodate and restrict the contact pieces; the lower electrode includes several rectangular electrode blocks that are adapted to the positioning grooves, and the top wall of the rectangular electrode blocks is provided with a first resistance pattern for contacting the bottom wall of the contact pieces.

[0010] A support platform is disposed above the machine base. An upper electrode is movably mounted on the support platform. The upper electrode is located above the lower electrode and can roll relative to the lower electrode to continuously weld the workpiece placed between the upper and lower electrodes. The upper electrode includes four fan-shaped electrode blocks evenly distributed circumferentially. The arc-shaped outer wall of the fan-shaped electrode blocks is provided with a second resistance pattern for contacting the top wall of the metal sheet.

[0011] An automatic feeding system is located on the side of the machine base and is used to automatically feed the metal sheets and contact sheets to be welded between the upper and lower electrodes in a feeding manner.

[0012] In the aforementioned automatic welding machine for thermal protectors, the lower electrode also includes an electrode base, which is movably installed inside the machine base; several rectangular electrode blocks are fixedly connected to the top wall of the electrode base, and the top wall of the rectangular electrode blocks is lower than the top wall of the positioning groove.

[0013] In the aforementioned automatic welding machine for thermal protectors, the electrode holder is slidably installed inside the machine base via a lifting seat. The lifting seat is driven by a first drive assembly to slide upward relative to the machine base to compensate for the wear caused by long-term contact between the top wall of the first resistive groove and the contact piece.

[0014] In the aforementioned automatic welding machine for thermal protectors, the support platform can reciprocate in the left and right directions relative to the machine base. A turntable is rotatably mounted on the support platform, and four sector-shaped electrode blocks are evenly distributed on the turntable along the circumference, with each sector-shaped electrode block being radially slidably connected to the turntable.

[0015] In the aforementioned automatic welding machine for thermal protectors, the sector-shaped electrode block is driven to slide radially on the turntable by a wedge-shaped pusher; the wedge-shaped pusher is frustum-shaped and is slidably connected to the turntable.

[0016] In the aforementioned automatic welding machine for thermal protectors, the wedge-shaped pusher is driven by the second drive assembly, which causes the fan-shaped electrode block to slide radially outward on the turntable to compensate for the wear caused by long-term contact between the top wall of the second resistance pattern and the metal sheet.

[0017] In the aforementioned automatic welding machine for thermal protectors, the gaps between the four sector-shaped electrode blocks correspond to the gap positions between two adjacent metal sheets.

[0018] In the aforementioned automatic welding machine for thermal protectors, the electrode holder, rectangular electrode block, and sector-shaped electrode block are all made of conductive material and are used to conduct welding current to the first resistance pattern and the second resistance pattern.

[0019] In the aforementioned automatic welding machine for thermal protectors, the extension directions of the first resistance pattern and the second resistance pattern intersect each other, forming a cross shape.

[0020] In the aforementioned automatic welding machine for thermal protectors, the automatic feeding system includes a metal sheet feeding mechanism for conveying metal sheets and a contact sheet feeding mechanism for conveying contact sheets.

[0021] Compared with existing technologies, the advantages of this invention are: 1. This invention achieves efficient continuous welding of contact components, reliable improvement of welding quality and significant extension of electrode life through automated assembly line operation, cross-shaped resistance pattern for current concentration and dual wear compensation structure of upper and lower electrodes, while reducing equipment and maintenance costs.

[0022] 2. By setting up an automatic feeding system, the contact pieces and metal pieces are continuously conveyed to the welding station in an automatic feeding manner. Combined with the support table that can move back and forth to drive the upper electrode to roll continuously, this replaces the inefficient operation mode of traditional manual feeding and welding one by one, realizing the automated production line welding of contact components (metal pieces and contact pieces).

[0023] 3. By setting a first resistance pattern on the top wall of the rectangular electrode block and a second resistance pattern on the outer ring wall of the fan-shaped electrode block, and the extension directions of the first resistance pattern and the second resistance pattern intersect each other to form a cross shape, the welding current is concentrated and guided to the texture intersection point at the contact interface between the metal sheet and the contact sheet. The local current density is significantly increased, and the generated resistance heat is more concentrated and efficient, which helps to quickly form a strong weld nugget.

[0024] 4. After the first resistance groove wears out, the lifting seat can slide upwards with a small distance, causing the electrode seat and rectangular electrode block to rise synchronously to compensate for the wear. Simultaneously, after the second resistance groove wears out, the wedge-shaped pusher can move forward to push the fan-shaped electrode block to slide radially outwards with a small distance to compensate for the wear. This dual wear compensation structure allows the upper and lower electrodes to restore their effective working surfaces through fine adjustments during long-term use, eliminating the need for frequent complete electrode replacement, significantly extending electrode lifespan, and reducing maintenance costs and equipment downtime. Furthermore, as an independent component, the fan-shaped electrode block only requires replacement of a single block after wear reaches its limit, further reducing consumable costs. Attached Figure Description

[0025] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings, wherein:

[0026] Figure 1 This is a schematic diagram of the overall structure;

[0027] Figure 2 This is a partially enlarged schematic diagram of the base, support platform, and upper electrode.

[0028] Figure 3 This is an enlarged schematic diagram of the contact sheet and metal sheet structure.

[0029] Figure 4 This is a cross-sectional view of the machine base.

[0030] Figure 5 This is an enlarged schematic diagram of the structure at point A in section 4;

[0031] Figure 6 for Figure 1 A schematic diagram of the side view structure;

[0032] Figure 7 This is a cross-sectional view of the turntable.

[0033] Figure 8 This is a schematic diagram of the sector-shaped electrode block before adjustment.

[0034] Figure 9 This is a schematic diagram of the adjusted sector-shaped electrode block.

[0035] In the diagram: 100, contact piece; 200, metal sheet; 1, machine base; 11, positioning groove; 12, lifting seat; 13, first drive assembly; 2, support platform; 21, turntable; 22, second drive assembly; 3, lower electrode; 31, electrode seat; 32, rectangular electrode block; 321, first resistance pattern; 4, upper electrode; 41, fan-shaped electrode block; 411, second resistance pattern; 42, wedge-shaped pusher; 5, automatic feeding system. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] Reference Figures 1 to 4 An automatic welding machine for thermal protectors is disclosed, used to weld contact pieces 100 to the welding surface of metal sheets 200. The automatic welding machine mainly includes a base 1, a support platform 2, a lower electrode 3, an upper electrode 4, and an automatic feeding system 5. After welding, the metal sheets 200 and contact pieces 100 together form the contact assembly in the thermal protector.

[0038] The base 1 serves as the mounting foundation for the entire device, and its top wall has several evenly distributed positioning grooves 11. The shape and size of the positioning grooves 11 are adapted to the contact piece 100 to accommodate and constrain the contact piece 100. The interior of the base 1 is hollow, forming an installation space to accommodate the lower electrode 3 component.

[0039] An automatic feeding system 5 is located on the side of the machine base 1 and is used to automatically feed the metal sheet 200 and contact piece 100 to be welded between the upper electrode 4 and the lower electrode 3. The automatic feeding system 5 includes a metal sheet feeding mechanism for feeding the metal sheet 200 and a contact piece feeding mechanism for feeding the contact piece 100.

[0040] It should be noted that, preferably, the metal sheet feeding mechanism can adopt a combination of automatic vibratory feeder feeding and conveyor belt conveying. The metal sheet feeding mechanism includes positioning pins that are adapted to the positioning holes on the metal sheet 200. Through the cooperation between the positioning pins and the positioning holes, the precise feeding and positioning of the metal sheet 200 can be achieved.

[0041] Preferably, the contact sheet feeding mechanism (not shown in the figure) is used to convey the contact sheets 100 in a row to the positioning groove 11 of the machine base 1. The contact sheet feeding mechanism can use a vibratory feeder to feed the material, which is then conveyed to the top of the positioning groove 11 via a sliding guide rail, and then pushed into the positioning groove 11 by a pushing mechanism.

[0042] The specific structure of the automatic feeding system 5 is not limited to the above-mentioned method. Any structure that can realize the automatic feeding of metal sheet 200 and contact sheet 100 can be adopted.

[0043] Preferably, a photoelectric sensor is provided at the entrance of the positioning groove 11 to detect whether the contact piece 100 has accurately fallen into the positioning groove 11; a metal piece 200 positioning detection sensor is provided in front of the upper electrode 4 to detect whether the metal piece 200 has been conveyed to the welding station. When the sensor detects an abnormality in material supply, the control system automatically suspends welding and issues an alarm signal, effectively preventing empty welding or misaligned welding caused by material shortage or misalignment.

[0044] Reference Figures 1 to 5 The lower electrode 3 is movably mounted on the base 1. The lower electrode 3 includes several rectangular electrode blocks 32, the number and position of which correspond one-to-one with the positioning grooves 11. The top wall of the rectangular electrode block 32 is provided with a first resistance pattern 321, which is used to contact the bottom wall of the contact piece 100 and performs the functions of conducting electricity and transmitting pressure during welding.

[0045] The lower electrode 3 includes an electrode base 31. The electrode base 31 is mounted vertically inside the base 1. Several rectangular electrode blocks 32 are fixedly connected to the top wall of the electrode base 31. The top wall of the rectangular electrode blocks 32 is lower than the top wall of the positioning groove 11, thereby forming a receiving space in the positioning groove 11 for accommodating the contact piece 100.

[0046] Specifically, the electrode holder 31 is slidably mounted inside the base 1 via the lifting seat 12. The lifting seat 12 is driven by the first drive assembly 13 and can slide slightly upward relative to the base 1. When the first resistance pattern 321 on the top wall of the rectangular electrode block 32 wears due to long-term contact with the contact piece 100, the first drive assembly 13 drives the lifting seat 12 to move slightly upward, causing the electrode holder 31 and the rectangular electrode block 32 to rise synchronously, thereby compensating for the wear of the first resistance pattern 321 and ensuring that the rectangular electrode block 32 always maintains good contact with the contact piece 100.

[0047] It should be noted that, as a preferred embodiment, a locking structure is provided between the lifting seat 12 and the base 1, so that the position of the electrode seat 31 and the base 1 is locked after the electrode seat 31 is adjusted to the correct position.

[0048] Reference Figures 1 to 2 , Figures 6 to 9 The support platform 2 is positioned above the base 1 and reciprocates left and right. An upper electrode 4 is movably mounted on the support platform 2. The upper electrode 4 is located directly above the lower electrode 3 and can roll relative to the lower electrode 3 to continuously weld workpieces placed between the upper and lower electrodes 3. The left-right reciprocating stroke of the support platform 2 covers the entire working stroke required for continuous welding. During continuous welding, the upper electrode 4 rolls continuously, completing the welding of a row of workpieces in one stroke, significantly improving welding output per unit time and effectively solving the problems of low efficiency in existing manual welding and high cost and difficult maintenance of multi-station welding machines.

[0049] Specifically, the support platform 2 is slidably mounted above the base 1 via a linear guide pair (not shown in the figure). A turntable 21 is rotatably mounted on the support platform 2. Four sector-shaped electrode blocks 41 are evenly distributed circumferentially on the turntable 21, and the four sector-shaped electrode blocks 41 are initially assembled into a circular disk-shaped structure. Each sector-shaped electrode block 41 is radially slidably connected to the turntable 21, and the outer ring wall of the sector-shaped electrode block 41 is provided with a second resistance groove 411 for contacting the top wall of the metal sheet 200.

[0050] When the second resistance pattern 411 of the sector electrode block 41 wears down due to long-term contact with the metal sheet 200, the sector electrode block 41 slides outward along the radial micro-pitch on the turntable 21 through the sliding seat (not shown in the figure, which can adopt a dovetail groove or T-groove structure to slide in cooperation with the turntable 21), thereby compensating for the wear of the second resistance pattern 411 and ensuring that the sector electrode block 41 always maintains good contact with the metal sheet 200.

[0051] The sector-shaped electrode block 41 slides radially on the turntable 21 driven by the wedge-shaped pusher 42. Specifically, the wedge-shaped pusher 42 is frustum-shaped, with its large end facing rearward and its small end facing forward. The wedge-shaped pusher 42 is slidably connected back and forth along the support platform 2. The wedge-shaped pusher 42 is driven by the second drive assembly 22. When the second drive assembly 22 drives the wedge-shaped pusher 42 to move forward, the inclined surface of the wedge-shaped pusher 42 pushes the sector-shaped electrode block 41 to move radially outward.

[0052] It should be noted that the splice of the fan-shaped electrode block 41 has a gap, which will widen after radial sliding extension. However, this splice always corresponds to the gap between two adjacent metal sheets 200, so that during the welding process, the break of the fan-shaped electrode block 41 is exactly above the gap between two adjacent metal sheets 200, and will not affect the welding area of ​​any metal sheet 200. This ensures that the upper electrode 4 and the metal sheet 200 form a continuous and uniform contact, and ensures that the welding process of each metal sheet 200 is continuous welding.

[0053] It should be noted that, as a preferred embodiment, a locking structure is provided between the sliding seat on the sector electrode block 41 and the turntable 21, so that after the sector electrode block 41 is adjusted to the position, the sector electrode block 41 is locked relative to the turntable 21.

[0054] During welding, the contact piece 100 is confined within the positioning groove 11 and supported from below by the rectangular electrode block 32; the metal sheet 200 covers the contact piece 100 and is pressed and rolled by the fan-shaped electrode block 41 of the upper electrode 4 from above. The welding current flows sequentially through the fan-shaped electrode block 41 of the upper electrode 4, the metal sheet 200, the contact piece 100, to the rectangular electrode block 32 of the lower electrode 3, and the electrode seat 31. Resistance heat is generated at the contact interface between the metal sheet 200 and the contact piece 100, forming a weld nugget.

[0055] The extension directions of the first resistance groove 321 and the second resistance groove 411 intersect each other, forming a cross shape. Specifically, the extension direction of the first resistance groove 321 is perpendicular to the rolling direction, and the extension direction of the second resistance groove 411 is parallel to the rolling direction. When the upper electrode 4 is rolled and welded, the first resistance groove 321 and the second resistance groove 411 form a cross-shaped indentation at the contact interface between the metal sheet 200 and the contact piece 100. This cross-shaped texture structure can concentrate the welding current, increasing the current density at the texture intersection. The increased current density generates higher local heat, which helps to quickly form a strong weld nugget at the contact interface between the contact piece 100 and the metal sheet 200, thereby improving welding quality and welding efficiency.

[0056] It is important to note that, to ensure maintainability after productization, the ratio of the texture depth of the first resistance pattern 321 to the thickness of the rectangular electrode block 32 is preferably controlled between 1:20 and 1:30. When the texture depth wears down to 60% of its initial value, it is compensated back to its initial height in one go by the first drive component 13. Similarly, the second resistance pattern 411 has two compensation margins reserved in the radial thickness direction of the fan-shaped electrode block 41. The compensation amount for each compensation is preferably 0.1mm to 0.2mm, and the number of compensations is recommended not to exceed three. After exceeding this, the fan-shaped electrode block 41 should be replaced to avoid local overheating caused by cracking of the electrode block or insufficient conductive cross-sectional area due to excessive material thinning.

[0057] The working process of the automatic welding machine for thermal protectors of the present invention is as follows: First, the contact piece feeding mechanism conveys the contact piece 100 into the positioning groove 11 of the machine base 1. After the contact piece 100 falls into the positioning groove 11, its bottom wall contacts the first resistance groove 321 on the top wall of the rectangular electrode block 32. The metal sheet feeding mechanism conveys the metal sheet 200 in a row between the upper electrode 4 and the lower electrode 3, so that the metal sheet 200 covers the top of the contact piece 100.

[0058] Then, the support platform 2 moves from left to right (or from right to left) at a preset speed, causing the entire upper electrode 4 to roll along the arrangement direction of the metal sheet 200. The second resistance groove 411 on the outer ring wall of the fan-shaped electrode block 41 contacts the top wall of the metal sheet 200. During the rolling process, the welding power supply is turned on, and the welding current flows through the upper electrode 4, the metal sheet 200, and the contact piece 100 before reaching the lower electrode 3.

[0059] Because the first resistance pattern 321 and the second resistance pattern 411 are arranged in a cross shape, the current is concentrated at the contact interface between the metal sheet 200 and the contact piece 100, generating local high temperature, which melts the metal at the contact interface to form a weld nugget. The upper electrode 4 rolls continuously, forming a continuous weld between the metal sheet 200 and the contact piece 100, thus completing the welding.

[0060] After welding is completed, the welded contact assembly is sent out, and the next set of metal sheets 200 and contact pieces 100 enter the welding station to begin the next welding cycle.

[0061] It should be noted that the electrode holder 31, rectangular electrode block 32, and sector-shaped electrode block 41 are all made of conductive materials, preferably copper alloys with good conductivity, such as chromium-zirconium copper. The positive terminal of the welding power source is connected to the sector-shaped electrode block 41 of the upper electrode 4 via a wire, and the negative terminal is connected to the electrode holder 31 or rectangular electrode block 32 of the lower electrode 3 via a wire, thereby conducting the welding current to the first resistance strip 321 and the second resistance strip 411.

[0062] The lifting seat 12 serves as an intermediate component connecting the electrode holder 31 and the base 1; the sliding seat serves as an intermediate component connecting the sector-shaped electrode block 41 and the turntable 21, and is preferably made of alumina ceramic or high-strength engineering plastic. If metal materials must be used due to load-bearing strength requirements, a ceramic insulating gasket should be added between the lifting seat 12 and the base 1, and a mica insulating layer should be added between the lifting seat 12 and the electrode holder 31 to ensure effective electrical isolation.

[0063] Preferably, the present invention provides circulating water cooling channels inside the turntable 21 and the lifting seat 12, respectively, with the cooling water temperature controlled between 15°C and 25°C. Through forced water cooling, the electrode working temperature can be controlled below 200°C, effectively maintaining the hardness and conductivity of the electrode material, extending the electrode life, and reducing the impact of radial dimension changes of the fan-shaped electrode block 41 caused by thermal expansion on the welding quality.

[0064] Preferably, the first drive assembly 13 and the second drive assembly 22 are formed by a servo motor connected to a precision ball screw via a coupling, with the ball screw nut fixedly connected to the lifting seat 12 or the wedge-shaped push block 42. When the servo motor rotates, the ball screw converts the rotational motion into the linear motion of the nut, driving the lifting seat 12 or the wedge-shaped push block 42 to achieve micro-sliding. The dual wear compensation structure allows both the upper and lower electrodes to restore their effective working surfaces through fine adjustments during long-term use, eliminating the need for frequent overall electrode replacement, significantly extending the electrode's service life, and reducing maintenance costs and equipment downtime. Simultaneously, the fan-shaped electrode block 41, as an independent component, only requires replacement of a single block after wear reaches its limit, further reducing consumable costs.

[0065] Currently, the mainstream welding methods for thermal protector contact assemblies are still manual placement and spot welding, or reliance on complex multi-station automatic welding machines. The former is inefficient and quality depends on manual labor, while the latter has high equipment costs and is difficult to maintain. Long-term wear of the electrode working surfaces during welding can lead to fluctuations in welding quality. Compared with existing technologies, this solution adds an automatic feeding system 5, a split fan-shaped electrode block 41 for the upper electrode 4, and a rectangular electrode block 32 for the lower electrode 3. Although these structures and the supporting servo drive and cooling system will increase the initial equipment cost, they can achieve fully automatic continuous welding of the metal sheet 200 and the contact piece 100, completing the welding of the entire row in one stroke. The current is concentrated by the cross-shaped resistance lines, and the electrode life is extended by the dual wear compensation structure of the upper and lower electrodes.

[0066] These new structures utilize conventional machining processes, making manufacturing and assembly relatively easy to control, and mass production is entirely feasible with existing machining capabilities. In the long run, single-machine efficiency is increased several times, significantly reducing labor costs per unit; electrode wear requires only minor adjustments rather than frequent complete replacements, drastically reducing consumable costs and downtime; stable welding quality reduces scrap rates, avoiding recall losses due to thermal protector failure caused by contact detachment; the equipment structure is relatively simple, with lower maintenance costs than multi-station welding machines. The initial investment in equipment is recovered through labor savings, consumable savings, and improved yield, forming a long-term, sustainable competitive advantage.

[0067] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0068] Furthermore, the terms "first," "second," "number one," and "number two" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first," "second," "number one," or "number two" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0069] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0070] The embodiments described herein are preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. An automatic welding machine for thermal protectors, used to weld contact pieces to the welding surface of a metal sheet, characterized in that, include: A base on which a lower electrode is movably mounted; The top wall of the base is provided with several evenly distributed positioning grooves, which are used to accommodate and restrict the contact pieces. The lower electrode includes several rectangular electrode blocks that are adapted to the positioning groove. The top wall of the rectangular electrode block is provided with a first resistance pattern for contacting the bottom wall of the contact piece. A support platform is provided above the machine base. An upper electrode is movably mounted on the support platform. The upper electrode is located above the lower electrode and can roll relative to the lower electrode to continuously weld the workpiece placed between the upper and lower electrodes. The upper electrode includes four fan-shaped electrode blocks evenly distributed along the circumference. The arc-shaped outer wall of the fan-shaped electrode blocks is provided with a second resistance pattern for contacting the top wall of the metal sheet. A turntable is rotatably mounted on the support platform. The sector-shaped electrode block is driven to slide radially on the turntable by a wedge-shaped pusher. The wedge-shaped pusher is driven by a second drive assembly, which drives the sector-shaped electrode block to slide radially outward on the turntable to compensate for the wear caused by long-term contact between the top wall of the second resistive texture and the metal sheet. An automatic feeding system is located on the side of the machine base and is used to automatically feed the metal sheets and contact sheets to be welded between the upper and lower electrodes in a feeding manner.

2. The automatic welding machine for thermal protectors according to claim 1, characterized in that, The lower electrode also includes an electrode base, which is movably installed inside the base; several rectangular electrode blocks are fixedly connected to the top wall of the electrode base, and the top wall of the rectangular electrode blocks is lower than the top wall of the positioning groove.

3. The automatic welding machine for thermal protectors according to claim 2, characterized in that, The electrode holder is slidably installed inside the base via a lifting seat. The lifting seat is driven by the first drive assembly to slide upward relative to the base, which is used to compensate for the wear caused by long-term contact between the top wall of the first resistive texture and the contact piece.

4. The automatic welding machine for thermal protectors according to claim 2, characterized in that, The support platform can reciprocate in the left and right directions relative to the machine base. Four sector-shaped electrode blocks are evenly distributed on the turntable along the circumference, and each sector-shaped electrode block is radially slidably connected to the turntable.

5. An automatic welding machine for thermal protectors according to claim 1, characterized in that, The wedge-shaped pusher is frustum-shaped and slides back and forth on the turntable.

6. An automatic welding machine for thermal protectors according to claim 4, characterized in that, The gaps between the four sector-shaped electrode blocks correspond to the gap positions between two adjacent metal sheets.

7. An automatic welding machine for thermal protectors according to claim 4, characterized in that, The electrode holder, rectangular electrode block, and sector-shaped electrode block are all made of conductive material and are used to conduct welding current to the first resistance pattern and the second resistance pattern.

8. An automatic welding machine for thermal protectors according to claim 7, characterized in that, The extension directions of the first resistance pattern and the second resistance pattern are intersected to form a cross shape.

9. An automatic welding machine for thermal protectors according to claim 1, characterized in that, The automatic feeding system includes a metal sheet feeding mechanism for conveying metal sheets and a contact sheet feeding mechanism for conveying contact sheets.

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