A connecting rod driven foot pedal spot welder

Abstract

This utility model discloses a linkage-driven foot-operated spot welding machine, belonging to the technical field of welding equipment. The spot welding machine includes a body, a fixed lower electrode arm, a movable upper electrode arm, a foot pedal, and a return spring, and also includes a linkage assembly. The linkage assembly includes: a triangular plate, the front corner of which is hinged to the rear side of the body; a lower linkage, the upper and lower ends of which are respectively hinged to the lower rear corner of the triangular plate and the rear end of the foot pedal; and an upper linkage, the lower end of which is hinged to the upper rear corner of the triangular plate, the upper end of which passes through the rear end of the movable upper electrode arm and is connected to the movable upper electrode arm via a buffer spring and a limiting component. The buffer spring is sleeved on the upper linkage and located below the movable upper electrode arm, used to apply an upward elastic force to the rear end of the movable upper electrode arm. This utility model achieves effort-saving transmission through the linkage of the triangular plate and the upper and lower linkages, and achieves flexible pressurization and smooth return through the buffer spring and pressure release component.

Description

Technical Field

[0001] This utility model relates to the field of welding equipment technology, and in particular to a linkage-driven foot-operated spot welding machine. Background Technology

[0002] Spot welding (resistance spot welding) is a widely used process in metal joining. It involves applying pressure to the workpiece through electrodes and passing a large current through it instantaneously, using the heat of contact resistance to melt the metal and form a weld nugget. Foot-operated spot welding machines occupy an important position in small and medium-sized enterprises, repair shops, and multi-variety, small-batch production due to their low cost, simple operation, and lack of need for air supply or servo systems.

[0003] Various transmission and buffering structures for foot-operated spot welding machines have been disclosed in the prior art. For example, Chinese utility model patent CN211072216U discloses a foot-operated spot welding machine, which includes a frame, an upper electrode arm, a lower electrode arm, a foot pedal, and a transmission mechanism. This patent uses a parallel four-bar linkage structure to transmit the lifting and lowering motion of the foot pedal to the upper electrode arm, and a spring buffer device is provided between the foot pedal and the frame to absorb the downward pressure impact. However, this patent has the following technical problems: First, the use of only spring buffer cannot provide a controllable damping effect, and there is still obvious rigid impact during the downward pressure process, which can easily cause indentations or deformation on the workpiece surface and accelerate the wear of the electrode head; Second, there is no adjustment device for the swing amplitude of the foot pedal, making it difficult for the operator to accurately control the welding pressure according to the workpiece thickness, resulting in poor adaptability; Third, the linkage structure between the foot pedal action and the start and stop of the welding current is not disclosed, and a manual button trigger is usually required, which poses a risk of response delay or misoperation.

[0004] Chinese utility model patent CN204053216U discloses a foot pedal transmission mechanism for a foot-operated spot welding machine, comprising a foot pedal, a transmission rod, a return spring, and a connecting arm. The core improvement of this patent lies in the use of a telescopic structure for the transmission rod, allowing the length to be adjusted by a nut to accommodate different operator needs. A limiting bolt is also provided between the foot pedal and the frame to limit the maximum downward pressure position of the foot pedal. However, this patent still has the following technical problems: First, the transmission rod is rigidly connected, and the impact is directly transmitted to the electrode during downward pressure without a flexible buffer structure, resulting in a strong impact. Second, the return relies solely on a single spring, and the spring rebound impact during the return stroke is unavoidable, easily leading to weld tearing or unintended contact between the electrode and the workpiece. Third, the limiting bolt can only limit the downward stroke in one direction and cannot limit the upward movement of the foot pedal, resulting in incomplete stroke control. Fourth, the synchronous triggering structure for starting and stopping the welding current is not disclosed, leaving room for improvement in operational convenience and safety.

[0005] Therefore, this utility model proposes a spot welding machine with improved structure and convenient operation, aiming to solve at least one of the technical problems in the prior art. Utility Model Content

[0006] To overcome the shortcomings of the prior art, the present invention adopts the following technical solution:

[0007] A linkage-driven foot-operated spot welding machine includes a machine body, a fixed lower electrode arm, a movable upper electrode arm, a foot pedal, and a return spring, and also includes a linkage assembly; the linkage assembly includes:

[0008] A triangular plate, the front corner of which is hinged to the rear side of the machine body;

[0009] The lower connecting rod is hinged at its upper and lower ends to the lower rear corner of the triangular plate and the rear end of the foot pedal, respectively.

[0010] An upper connecting rod has its lower end hinged to the upper rear corner of the triangular plate. The upper end of the upper connecting rod passes through the rear end of the movable upper electrode arm and is connected to the movable upper electrode arm via a buffer spring and a limiting member. The buffer spring is sleeved on the upper connecting rod and located below the movable upper electrode arm, and is used to apply an upward elastic force to the rear end of the movable upper electrode arm. The limiting member is located at the upper end of the upper connecting rod and above the rear end of the movable upper electrode arm, and is used to push the rear end of the movable upper electrode arm to swing downward when the upper connecting rod moves downward.

[0011] Furthermore, a pressure relief component is provided between the upper connecting rod and the movable upper electrode arm, the pressure relief component comprising:

[0012] The outer cylinder has an open end that is in a sealing sliding fit with the upper connecting rod;

[0013] The drive rod has its lower end coaxially connected to the closed end of the outer cylinder, and its upper end passes through the buffer spring and the rear end of the movable upper electrode arm in sequence before connecting to the limiting member.

[0014] A piston, fixed to the upper end of the upper connecting rod and slidably disposed in the outer cylinder, divides the inner cavity of the outer cylinder into an upper chamber and a lower chamber, the upper chamber and the lower chamber being filled with a fluid medium; the piston is provided with a quick pressure relief valve that allows fluid to flow from the upper chamber to the lower chamber and a one-way valve that only allows fluid to flow from the lower chamber to the upper chamber.

[0015] Furthermore, a transition piece is provided between the buffer spring and the movable upper electrode arm. The top of the transition piece is an arched structure, and the bottom of the rear end of the movable upper electrode arm is provided with an arc-shaped groove that cooperates with the arched structure. The radius of curvature of the arched structure is smaller than the radius of curvature of the arc-shaped groove.

[0016] Furthermore, the front bottom of the machine body is provided with a travel limiting structure for limiting the vertical swing amplitude of the foot pedal. The travel limiting structure includes a limiting plate, which is fixedly installed on the front bottom of the machine body. The limiting plate has extensions at both the upper and lower ends on the side facing the foot pedal, with the two extensions located above and below the foot pedal, respectively.

[0017] Furthermore, each of the extensions is vertically provided with an axially adjustable limiting post, the end of the limiting post facing the foot pedal being used to abut against the foot pedal.

[0018] Furthermore, an extension rod is fixedly connected to one side of the triangular plate, and the trigger switch of the machine body has a rotatable trigger part, which is correspondingly arranged with the extension rod. When the triangular plate is flipped upward, the extension rod presses against the trigger part to rotate it and trigger the trigger switch.

[0019] Furthermore, the trigger part is provided with a roller, and the extension rod presses against the trigger part through the roller.

[0020] Furthermore, the movable upper electrode arm includes an electrode body and a connecting rod, the electrode body and the connecting rod are fixedly connected, and the front end of the connecting rod is hinged to the front side of the machine body.

[0021] Furthermore, the limiting post is an axially adjustable bolt, and the extension is provided with a threaded hole that mates with the bolt.

[0022] Furthermore, the limiting component is an axially adjustable nut, and the upper end of the upper connecting rod is provided with an external thread that mates with the nut.

[0023] Compared with the prior art, the beneficial effects of this utility model are:

[0024] 1. The linkage assembly consisting of a triangular plate and upper and lower connecting rods converts the lifting motion of the foot pedal into the lifting motion of the upper electrode arm, optimizing the lever arm ratio. Compared with the parallel four-bar structure and telescopic transmission rod in the existing technology, the triangular plate structure can achieve a larger upper electrode arm stroke with less pedaling force, significantly reducing the operator's labor intensity and reducing fatigue even during long-term continuous operation.

[0025] 2. A buffer spring provides flexible cushioning, while pressure relief components (outer cylinder, upper connecting rod, piston, quick-release valve, and check valve) provide a controllable pressure release effect. During the downward pressing phase of the upper electrode arm, when the driving pressure is too fast, fluid flows through the quick-release valve, causing the front end of the movable upper electrode arm to descend slowly relative to the foot pedal, effectively avoiding workpiece indentation and electrode wear caused by rigid impact in existing technologies.

[0026] 3. The stroke limit structure can precisely limit the up and down swing amplitude of the foot pedal by adjusting the axial position of the upper and lower limit columns, thereby controlling the stroke of the upper electrode arm and the welding pressure.

[0027] 4. The extension rod fixedly connected to the triangular plate is linked to the trigger part (with roller) of the machine body trigger switch. When the foot pedal is pressed down to the predetermined position, the extension rod presses against the trigger part to automatically connect the welding current, so as to achieve precise synchronization between the foot pedal action and the start and stop of welding.

[0028] 5. It integrates multiple functions such as triangular plate transmission, spring buffer, pressure release, stroke limit, and trigger linkage into one unit, while maintaining the low-cost advantage of foot-operated spot welding machines, it significantly improves operating comfort, welding stability, and process adaptability. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the structure of an embodiment of the present utility model;

[0030] Figure 2 This is a structural schematic diagram from another perspective of an embodiment of the present utility model;

[0031] Figure 3 This is a structural schematic diagram from another perspective of an embodiment of the present utility model;

[0032] Figure 4 This is a cross-sectional view of the pressure relief component in an embodiment of this utility model.

[0033] In the diagram: 1. Body; 11. Trigger switch; 111. Roller; 2. Fixed lower electrode arm; 3. Movable upper electrode arm; 31. Electrode body; 32. Connecting rod; 4. Foot pedal; 5. Reset spring; 6. Linkage assembly; 61. Triangular plate; 611. Extension rod; 62. Lower connecting rod; 63. Upper connecting rod; 64. Buffer spring; 65. Limiting component; 66. Pressure release component; 661. Outer cylinder; 662. Drive rod; 663. Piston; 664. Quick pressure relief valve; 665. One-way valve; 67. Transition component; 7. Stroke limiting structure; 71. Limiting plate; 72. Extension; 73. Limiting post. Detailed Implementation

[0034] In the description of this utility model, it should be understood that the terms "upper," "lower," "front," "rear," "left," and "right," 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 this utility model, and do not indicate or imply that the device or element referred to must have a specific orientation. The term "end" refers to the end region in the length direction of a component, and "side" refers to the side region in the width direction of a component. The term "provided with" should be understood as "provided with" or "assembled with," and does not limit the specific connection method. The term "corresponding" is used to describe the relative positional relationship, functional cooperation relationship, or spatial alignment relationship between two components.

[0035] Example 1, as Figures 1 to 3 As shown, a linkage-driven foot-operated spot welding machine includes a body 1, a fixed lower electrode arm 2, a movable upper electrode arm 3, a foot pedal 4, and a return spring 5. One end of the return spring 5 is connected to the foot pedal 4, and the other end is connected to the body 1, used to pull the foot pedal 4 back to its initial position after it is released. The spot welding machine also includes a linkage assembly 6, used to transmit the lifting and lowering motion of the foot pedal 4 to the movable upper electrode arm 3, thereby realizing the pressure action during welding.

[0036] The linkage assembly 6 includes a triangular plate 61, a lower linkage 62, and an upper linkage 63. The triangular plate 61 has a triangular structure, and its front corner is hinged to the rear side of the body 1 via a hinge axis, allowing the triangular plate 61 to swing around the hinge axis in a vertical plane. The upper and lower ends of the lower linkage 62 are respectively hinged to the lower rear corner of the triangular plate 61 and the rear end of the foot pedal 4 via hinge axes. The lower end of the upper linkage 63 is hinged to the upper rear corner of the triangular plate 61 via a hinge axis.

[0037] The upper end of the upper connecting rod 63 passes through the rear end of the movable upper electrode arm 3 and is connected to the movable upper electrode arm 3 via a buffer spring 64 and a limiting member 65. Specifically, the upper end of the upper connecting rod 63 is provided with an external thread, and the limiting member 65 is a nut with an internal thread, which is screwed onto the upper end of the upper connecting rod 63. The buffer spring 64 is sleeved on the upper connecting rod 63 and is located below the rear end of the movable upper electrode arm 3.

[0038] The upper end of the buffer spring 64 elastically abuts against the bottom rear end of the movable upper electrode arm 3. Preferably, a transition piece 67 is provided between the buffer spring 64 and the movable upper electrode arm 3. The top of the transition piece 67 is an arched structure, and the bottom rear end of the movable upper electrode arm 3 is provided with an arc-shaped groove that mates with the arched structure. The radius of curvature of the arched structure is smaller than the radius of curvature of the arc-shaped groove, so that the transition piece 67 and the movable upper electrode arm 3 form a line contact or a small area contact, which ensures stable contact between the two and allows slight relative rotation between the upper connecting rod 63 and the rear end of the movable upper electrode arm 3 during operation, avoiding jamming. The upper end of the buffer spring 64 elastically abuts against the bottom of the transition piece 67, and the lower end elastically abuts against the stepped surface on the upper connecting rod 63 or a fixed abutment structure (such as a retaining ring, not shown in the figure).

[0039] The limiting member 65 is disposed at the upper end of the upper connecting rod 63 and located above the rear end of the movable upper electrode arm 3. By rotating the limiting member 65, its axial position can be adjusted, thereby adjusting the pre-compression of the buffer spring 64, and thus adjusting the initial position of the upper connecting rod 63 relative to the movable upper electrode arm 3.

[0040] During operation, the operator presses down on the front end of foot pedal 4, causing it to swing downwards around its front fulcrum and its rear end to rise upwards. The lower connecting rod 62 moves upwards with the rear end of foot pedal 4, pushing the triangular plate 61 to rotate counterclockwise around its front corner hinge axis (from...). Figure 2 (View from above). When the triangle 61 rotates, the upper connecting rod 63 above it is pushed upward, and the upper end of the upper connecting rod 63 slides upward along the hole at the rear end of the movable upper electrode arm 3, while compressing the buffer spring 64. As the upper connecting rod 63 continues to rise, the buffer spring 64 is further compressed, generating an upward thrust on the rear end of the movable upper electrode arm 3 through the transition piece 67, causing the front end of the movable upper electrode arm 3 to press downward against the fixed lower electrode arm 2, completing the welding pressure. After releasing the foot pedal 4, the return spring 5 pulls the foot pedal 4 back to the initial position, and the upper connecting rod 63 returns to its original position downward under the elastic force of the return spring 5 and the buffer spring 64. The limiting piece 65 moves downward with the upper connecting rod 63 and pushes against the rear end of the movable upper electrode arm 3, causing the front end of the movable upper electrode arm 3 to lift upward and return to its original position.

[0041] In this embodiment, the linkage between the triangular plate 61 and the upper and lower connecting rods realizes the conversion of the lifting and lowering motion of the foot pedal 4 to the lifting and lowering motion of the movable upper electrode arm 3. At the same time, the buffer spring 64 provides flexible pressure to avoid rigid impact. After the front end of the movable upper electrode arm 3 contacts the workpiece, it is further compressed by the buffer spring 64 to prevent the front end of the movable upper electrode arm 3 (i.e., the spot welding pen) from being damaged due to excessive pressure.

[0042] Example 2, as Figures 1 to 4As shown, a linkage-driven foot-operated spot welding machine is described in this embodiment. Based on the first embodiment, a pressure relief component 66 is further added to improve the stability of the welding process.

[0043] A pressure release component 66 is also provided between the upper connecting rod 63 and the movable upper electrode arm 3. The pressure release component 66 includes an outer cylinder 661, a drive rod 662, a piston 663, a quick pressure relief valve 664, and a one-way valve 665.

[0044] The outer cylinder 661 is a cylindrical body, with its open end in a sealed sliding fit with the upper connecting rod 63. The drive rod 662 is a solid rod, with its lower end coaxially connected to the closed end of the outer cylinder 661, for example, by welding or threaded connection. The upper end of the drive rod 662 passes sequentially through the buffer spring 64, the transition piece 67, and the rear end of the movable upper electrode arm 3, and is then threadedly connected to the limiting piece 65. The piston 663 is fixed to the lower end of the upper connecting rod 63 and slides in a sealed fit with the inner wall of the outer cylinder 661, thereby dividing the inner cavity of the outer cylinder 661 into an upper chamber above the piston 663 and a lower chamber below the piston 663. The upper chamber and the lower chamber are filled with a fluid medium (e.g., hydraulic oil).

[0045] The upper end of the buffer spring 64 elastically abuts against the bottom of the transition member 67, and the lower end elastically abuts against the closed end of the outer cylinder 661.

[0046] The piston 663 is provided with a quick-release valve 664 that allows fluid to flow from the upper chamber to the lower chamber and a one-way valve 665 that only allows fluid to flow from the lower chamber to the upper chamber.

[0047] During operation, when the operator depresses foot pedal 4 too quickly, the upper connecting rod 63 moves upward, and the piston 663 moves upward accordingly. At this time, the pressure of the fluid medium in the upper chamber increases. Since the one-way valve 665 only allows fluid to flow from the lower chamber to the upper chamber, it is currently closed. When the pressure of the fluid medium in the upper chamber rises to the preset value of the quick-release valve 664, the quick-release valve 664 opens, and the fluid medium in the upper chamber flows to the lower chamber through the quick-release valve 664. The upward speed of the outer cylinder 661 relative to the upper connecting rod 63 slows down, thus producing a significant pressure release effect. This pressure release effect avoids rigid impact caused by rapid downward pressure, improving the safety and stability of the welding process.

[0048] When the foot pedal 4 is released, the upper connecting rod 63 returns to its original position downwards, and the piston 663 moves downwards accordingly. At this time, the volume of the lower chamber decreases, and the volume of the upper chamber increases. The pressure of the fluid medium in the lower chamber increases, the one-way valve 665 opens, and the fluid medium flows rapidly from the lower chamber to the lower chamber. The buffer spring 64 quickly returns to its original position, and then the front end of the movable upper electrode arm 3 is lifted.

[0049] Example 3, as Figures 1 to 3 As shown, a linkage-driven foot-operated spot welding machine is provided in this embodiment. Based on embodiment one or embodiment two, a stroke limiting structure 7 is further provided to precisely control the up-and-down swing amplitude of the foot pedal 4, thereby controlling the welding pressure.

[0050] The front bottom of the body 1 is provided with a travel limiting structure 7 for limiting the vertical swing amplitude of the foot pedal 4. The travel limiting structure 7 includes a limiting plate 71, which is a rectangular metal plate and is fixedly installed to the front bottom of the body 1 by bolts. The limiting plate 71 has extensions 72 at both the upper and lower ends on the side facing the foot pedal 4, with the two extensions 72 located above and below the foot pedal 4, respectively.

[0051] Each extension 72 is vertically perforated with an axially adjustable limiting post 73. The limiting post 73 is a bolt, and the extension 72 has a threaded hole that mates with the bolt. The end of the limiting post 73 facing the foot pedal 4 is used to abut against the foot pedal 4. By rotating the limiting post 73, its extension length can be adjusted, thereby adjusting the maximum downward or upward swing position of the foot pedal 4.

[0052] In use, the operator can rotate the lower limit post 73 to limit the maximum descent depth of the foot pedal 4 according to the workpiece thickness and the required welding pressure, so as to prevent excessive pressure from damaging the workpiece; and rotate the upper limit post 73 to limit the maximum rise height of the foot pedal 4.

[0053] Example 4, as Figures 1 to 3 As shown, a linkage-driven foot-operated spot welding machine is provided in this embodiment. Based on Embodiment 1, Embodiment 2 or Embodiment 3, a trigger switch linkage structure is further provided to realize the synchronous control of foot pedal action and welding current start and stop.

[0054] An extension rod 611 is fixedly connected to one side of the triangular plate 61 by welding or bolts, and the extension rod 611 extends outward from the side of the triangular plate 61. The trigger switch 11 of the machine body 1 has a rotatable trigger part, which is a lever structure with a rotating shaft. The trigger part is correspondingly arranged with the extension rod 611, that is, when the triangular plate 61 rotates to a predetermined position, the extension rod 611 can contact and press against the trigger part. The trigger part is provided with a roller 111, which is rotatably mounted to the end of the trigger part via a shaft. The extension rod 611 presses against the trigger part through the roller 111 to reduce friction, improve the sensitivity of the action and the service life.

[0055] During operation, when the operator presses the foot pedal 4, the triangular plate 61 flips upward, and the extension rod 611 moves upward accordingly. When the triangular plate 61 rotates to a predetermined angle, the extension rod 611 contacts the roller 111 and continues to move upward, thereby pressing against the trigger part to rotate, and the trigger switch 11 is turned on. The trigger switch 11 is electrically connected to the welding power supply control circuit inside the machine body 1. When the trigger switch 11 is turned on, the welding power supply is triggered, outputting welding current to the fixed lower electrode arm 2 and the movable upper electrode arm 3, and welding begins. When the foot pedal 4 is released, the triangular plate 61 flips downward, the extension rod 611 disengages from the roller 111, the trigger part rotates under the action of its own return spring, the trigger switch 11 is turned off, the welding power supply stops outputting welding current, and welding ends.

[0056] The trigger switch 11 is a micro switch or limit switch with normally open contacts, which is connected in series in the start control circuit of the welding power supply to control the start and stop of the welding power supply.

[0057] If the welding power supply control circuit inside the machine body 1 uses a contactor or relay as an intermediate control element, the trigger switch 11 is connected in series in the contactor coil circuit of the welding power supply. When the trigger switch 11 is turned on, the contactor coil is energized, the main contacts of the contactor are closed, and the welding power supply outputs welding current to the electrode.

[0058] In this embodiment, the extension rod 611 is linked with the roller 111 of the trigger switch 11 to realize automatic synchronous control of foot pedal action and welding current start and stop, avoiding the cumbersome operation of manual control of the switch required by traditional spot welding machines, and improving welding efficiency and safety.

[0059] Structures, components, and connection methods not described in detail in this utility model are all prior art known to those skilled in the art unless otherwise specified. It is obvious to those skilled in the art that this utility model is not limited to the details of the above exemplary embodiments, and that this utility model can be implemented in other specific forms without departing from the spirit or basic characteristics of this utility model. Therefore, the above embodiments should be regarded as exemplary and non-limiting in all respects. The scope of this utility model is defined by the appended claims rather than the foregoing description. Therefore, it is intended to include all changes falling within the meaning and scope of the equivalents of the claims within this utility model.

Claims

1. A linkage-driven foot-operated spot welding machine, comprising a machine body (1), a fixed lower electrode arm (2), a movable upper electrode arm (3), a foot pedal (4), and a return spring (5), characterized in that, It also includes a linkage assembly (6); the linkage assembly (6) includes: A triangular plate (61) has its front corner hinged to the rear side of the body (1); The lower connecting rod (62) is hinged at its upper and lower ends to the lower rear corner of the triangular plate (61) and the rear end of the foot pedal (4), respectively. The upper connecting rod (63) is hinged at its lower end to the upper rear corner of the triangular plate (61). The upper end of the upper connecting rod (63) passes through the rear end of the movable upper electrode arm (3) and is connected to the movable upper electrode arm (3) through a buffer spring (64) and a limiting member (65). The buffer spring (64) is sleeved on the upper connecting rod (63) and located below the movable upper electrode arm (3), and is used to apply an upward elastic force to the rear end of the movable upper electrode arm (3). The limiting member (65) is located at the upper end of the upper connecting rod (63) and above the rear end of the movable upper electrode arm (3), and is used to push the rear end of the movable upper electrode arm (3) downward when the upper connecting rod (63) moves downward.

2. The linkage-driven foot-operated spot welding machine according to claim 1, characterized in that, A pressure release element (66) is also provided between the upper connecting rod (63) and the movable upper electrode arm (3), the pressure release element (66) comprising: The outer cylinder (661) has its open end in a sealed sliding fit with the upper connecting rod (63); The drive rod (662) has its lower end coaxially connected to the closed end of the outer cylinder (661), and its upper end passes through the rear end of the buffer spring (64) and the movable upper electrode arm (3) in sequence, and is then connected to the limiting member (65). A piston (663) is fixed to the upper end of the upper connecting rod (63) and slidably disposed inside the outer cylinder (661), dividing the inner cavity of the outer cylinder (661) into an upper chamber and a lower chamber, the upper chamber and the lower chamber being filled with a fluid medium; the piston (663) is provided with a quick pressure relief valve (664) that allows fluid to flow from the upper chamber to the lower chamber and a one-way valve (665) that only allows fluid to flow from the lower chamber to the upper chamber.

3. The linkage-driven foot-operated spot welding machine according to claim 1 or 2, characterized in that, A transition piece (67) is provided between the buffer spring (64) and the movable upper electrode arm (3). The top of the transition piece (67) is an arched structure, and the bottom of the rear end of the movable upper electrode arm (3) is provided with an arc-shaped groove that cooperates with the arched structure. The radius of curvature of the arched structure is smaller than the radius of curvature of the arc-shaped groove.

4. The linkage-driven foot-operated spot welding machine according to claim 1, characterized in that, The front bottom of the body (1) is provided with a travel limiting structure (7) for limiting the up and down swing amplitude of the foot pedal (4). The travel limiting structure (7) includes a limiting plate (71). The limiting plate (71) is fixedly installed on the front bottom of the body (1). The limiting plate (71) has extensions (72) at both the upper and lower ends on the side facing the foot pedal (4). The two extensions (72) are located above and below the foot pedal (4) respectively.

5. The linkage-driven foot-operated spot welding machine according to claim 4, characterized in that, Each of the extensions (72) is vertically provided with an axially adjustable limiting post (73), the end of the limiting post (73) facing the foot pedal (4) is used to abut against the foot pedal (4).

6. The linkage-driven foot-operated spot welding machine according to claim 1, characterized in that, An extension rod (611) is fixedly connected to one side of the triangular plate (61). The trigger switch (11) of the body (1) has a rotatable trigger part. The trigger part is correspondingly arranged with the extension rod (611). When the triangular plate (61) is flipped upward, the extension rod (611) presses against the trigger part to make it rotate and trigger the trigger switch (11).

7. The linkage-driven foot-operated spot welding machine according to claim 6, characterized in that, The trigger part is provided with a roller (111), and the extension rod (611) presses against the trigger part through the roller (111).

8. The linkage-driven foot-operated spot welding machine according to claim 1, characterized in that, The movable upper electrode arm (3) includes an electrode body (31) and a connecting rod (32). The electrode body (31) and the connecting rod (32) are fixedly connected, and the front end of the connecting rod (32) is hinged to the front side of the body (1).

9. The linkage-driven foot-operated spot welding machine according to claim 5, characterized in that, The limiting post (73) is an axially adjustable bolt, and the extension (72) is provided with a threaded hole that mates with the bolt.

10. The linkage-driven foot-operated spot welding machine according to claim 1, characterized in that, The limiting member (65) is an axially adjustable nut, and the upper end of the upper connecting rod (63) is provided with an external thread that mates with the nut.

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