A rotating platform welding device for table legs

Abstract

The utility model discloses a kind of rotary platform type welding devices for table leg, belong to metal furniture manufacturing technical field, for the technical problem that traditional welding tool exists welding dead angle in table leg joint place, influence weld quality uniformity due to structure shielding.Solution points include: welding machine is connected with rotary platform rotation, and the seat plate top surface of rotary platform is equipped with positioning part and fixed part;Positioning part is made of crossbar positioning groove and two vertical rod positioning blocks, and crossbar positioning groove is matched with crossbar bottom surface, and vertical rod positioning block is arranged in groove body same side limit vertical rod in parallel;Fixed part uses the top pressing mechanism of transverse swing to press down table leg tightly;The seat plate is opened lateral open U-shaped groove, and its contour surrounds the joint of crossbar and vertical rod, so that welding position is 360° exposed after being fixed.The device is cooperatively designed through rotary platform and U-shaped groove, realizes full circumferential dead angle welding in table leg joint place, and is mainly used to improve the welding quality and efficiency of table leg ring seam.

Description

Technical Field

[0001] This utility model relates to the field of table and chair production equipment technology, and in particular to a rotating platform welding device for table legs. Background Technology

[0002] In the field of metal furniture manufacturing, table legs are typically constructed by symmetrically welding a horizontal bar and two vertical bars on the same side of the horizontal bar to form a π or L-shaped structure. The welding process for this structure faces the following technical challenges:

[0003] 1. Because the joint between the horizontal and vertical bars forms a three-dimensional fillet weld, traditional fixed tooling platforms will obstruct part of the welding area, preventing the welding torch from reaching the rear and bottom areas of the joint. This obstruction stems from the physical encapsulation of the workpiece by the tooling positioning block and clamping mechanism, requiring the operator to repeatedly disassemble and adjust the workpiece position to complete the entire welding process. This not only reduces efficiency but also easily leads to weld misalignment due to repeated positioning.

[0004] 2. During clamping, it is necessary to simultaneously ensure the axial position of the horizontal bar, the symmetry of the vertical bar, and its perpendicularity to the horizontal bar. Current technology uses split positioning blocks and manual bolts for clamping, requiring the operator to use both hands to hold the horizontal and vertical bars while simultaneously tightening the clamping fixture. Even slight mishaps can cause workpiece displacement. The root cause of this problem is that the workpiece needs to be simultaneously constrained in three degrees of freedom, while traditional tooling lacks a collaborative positioning mechanism, resulting in longer clamping times for single pieces and impacting efficiency.

[0005] 3. When welding thin-walled pipes with a wall thickness of 1.5-3mm, localized high temperatures cause uneven thermal expansion in the joint area. Since the free ends of the vertical rods in the π or L-shaped structure are unconstrained, heat conduction along the axial direction of the horizontal rods can cause the ends of the vertical rods to shift outwards, resulting in workpiece deformation. Although cold straightening after welding can be attempted, it will reduce the material's fatigue strength and add extra processing steps.

[0006] The technical essence of the above problems lies in the mismatch between the tooling structure design and the spatial position of the weld, leading to spatial obstruction; insufficient coordination of multi-degree-of-freedom constraints resulting in inefficient positioning; and thermal deformation stemming from localized high heat input coupled with insufficient heat dissipation. Past attempts at improvement have faced a dilemma: increasing the tooling clearance space weakens positioning stability; strengthening the heat dissipation structure increases the risk of welding interference. Therefore, improving efficiency while ensuring quality has become a pressing technical problem to be solved. Utility Model Content

[0007] This invention aims to solve the following problem: In the welding of metal table legs, a three-dimensional fillet weld is formed at the joint of the horizontal and vertical bars. Traditional fixed fixtures, due to the obstruction of positioning blocks and clamping structures, prevent the welding torch from reaching the rear and bottom areas of the joint. Operators must repeatedly disassemble the workpiece and adjust its posture to complete the entire circumference weld, which is not only inefficient but also prone to weld misalignment due to repeated positioning. The root cause of this problem lies in the fact that the fixture structure does not consider the full circumference of the weld.

[0008] To achieve these objectives and other advantages of this utility model, this utility model provides a rotating platform welding device for table legs, wherein the table legs are composed of a horizontal bar and two vertical bars symmetrically welded on the same side of the horizontal bar, and includes a welding machine and a rotating platform.

[0009] The rotating platform is rotatably connected to the welding machine, and the rotating platform includes:

[0010] The base plate, the top surface of which serves as the workpiece support surface;

[0011] The positioning part includes a horizontal bar positioning groove and several vertical bar positioning blocks on the seat plate; the horizontal bar positioning groove is located in the length direction of the seat plate and the groove opening matches the shape of the bottom surface of the horizontal bar; several vertical bar positioning blocks are arranged side by side on the same side of the horizontal bar positioning groove and respectively abut against and limit the side of the two vertical bars.

[0012] The fixing part is a horizontally swingable clamping mechanism, which is set on the seat plate and is used to clamp the table legs downwards to the horizontal bar positioning groove and the vertical bar positioning block;

[0013] The seat plate has a U-shaped groove extending inward from the edge. The outline of the U-shaped groove surrounds the joint between the horizontal and vertical bars, so that the welded parts of the table legs are exposed 360° around the circumference after they are fixed.

[0014] When the length of the table leg crossbar changes, the existing tooling needs to be replaced with the entire positioning module to adapt to different sizes. Because there is no reference positioning structure on the end face of the crossbar, workers need to repeatedly measure and adjust the axial position, increasing the time spent clamping each piece. Preferably, the base plate of this invention also provides a crossbar reference block, which is mounted on the base plate via a lateral adjustment mechanism and located at the end of the crossbar. The side of the crossbar reference block facing the end of the crossbar forms a vertical reference surface, used to abut against the end face of the crossbar to define the position of the crossbar in the length direction.

[0015] Traditional bolt tightening methods require two-hand operation: one hand to hold the workpiece while the other tightens the clamp. During tightening, the workpiece is prone to shifting, making this operation inefficient and posing safety hazards. Preferably, the tightening mechanism of this invention includes:

[0016] The hydraulic swing cylinder is vertically fixed to the workpiece support surface of the base plate, and its output shaft has the functions of synchronous rotation and linear lifting.

[0017] The first clamping arm has its first end rigidly connected to the output shaft of the hydraulic swing cylinder so that it can be driven by the hydraulic swing cylinder to perform simultaneous rotation and lifting movements.

[0018] The second clamping arm is connected to the second end of the first clamping arm by a bolted connector, and the bolted connector allows adjustment of the included angle between the second clamping arm and the first clamping arm to adjust the support position at its end; the end of the second clamping arm is provided with a downwardly extending clamping foot.

[0019] When the table leg is not in the positioning part, the hydraulic swing cylinder drives the second clamping arm to swing laterally to the clearance position; after the table leg is positioned, the hydraulic swing cylinder drives the second clamping arm to swing directly above the crossbar, and simultaneously drives the clamping foot to press down to clamp the table leg.

[0020] When continuously circumferentially welding thin-walled pipes with a wall thickness of 1.5-3mm, heat in the weld zone is conducted axially along the crossbar, causing the temperature rise of pipe sections far from the weld to exceed 200°C. Due to the difference in thermal expansion coefficients, the crossbar undergoes axial elongation deformation, which in turn pulls on the vertical bar, leading to post-weld deformation. Conventional air-cooling devices are inefficient because they cannot be integrated into the workpiece. Preferably, the crossbar reference block of the present invention has an axially penetrating airflow channel inside, which includes:

[0021] The air intake port is located at the end of the crossbar reference block facing away from the vertical reference plane, and is connected to an external compressed air source.

[0022] The air vent assembly is located on the vertical reference plane and is directly opposite the hollow inner cavity at the end of the crossbar.

[0023] When the end face of the crossbar abuts against the vertical reference plane, the air outlet group connects with the hollow inner cavity of the crossbar to form an axial heat dissipation channel.

[0024] Because the clamping foot and the workpiece surface are in smooth metal contact, the workpiece is prone to slight slippage due to centrifugal force when the rotating platform rotates at high speed. Preferably, the bottom of the clamping foot of the present invention is embedded with a knurled pressure head, the knurling depth of the surface of the pressure head is 0.2mm, and the knurling angle is 90°.

[0025] Preferably, the side of the vertical rod positioning block of the present invention is provided with an elastic protrusion, the protrusion height of which is 0.5-1mm, for forming an interference fit with the side of the vertical rod.

[0026] When the workpiece is placed into the fixture, the horizontal bar must be precisely embedded in the positioning groove, and the vertical bar must be simultaneously aligned with the positioning block. Because the workpiece is not pre-fixed, even slight vibrations can cause misalignment, requiring workers to make simultaneous fine adjustments with both hands. This operation is difficult and requires a long training period, essentially due to the lack of initial positioning assistance. Preferably, the bottom of the horizontal bar positioning groove of this invention is provided with a first permanent magnet group; the vertical bar abutment surface of the vertical bar positioning block is embedded with a second permanent magnet group, the surface of the second permanent magnet group being 0.5-1mm lower than the abutment surface; the permanent magnet group is ≥20mm away from the nearest welding part.

[0027] The first and second permanent magnet groups interact with the horizontal and vertical bars respectively through non-contact magnetic attraction, which is used for magnetic pre-positioning when placing the workpiece.

[0028] This utility model has at least the following beneficial effects:

[0029] 1. This utility model, through the coordinated design of the U-shaped groove and the rotating platform, fully exposes the joint between the horizontal and vertical bars to the welding torch's working space. The operator can perform full-circumferential welding of the joint without disassembling the workpiece, eliminating welding blind spots caused by physical obstruction in traditional tooling. The entire weld seam is completed in a single workpiece clamping, significantly improving welding position consistency and reducing labor intensity.

[0030] 2. This utility model's adjustable crossbar reference block adapts to workpieces of different lengths and specifications through axial position adjustment. Workers only need to slide the reference block to the scale mark to complete the changeover. End face reference positioning ensures stable axial position accuracy of the crossbar, avoiding repeated measurements and adjustments, significantly shortening production line changeover time and reducing reliance on operator skills.

[0031] 3. The clamping mechanism of this utility model adopts a hydraulic swing cylinder with integrated synchronous rotation and linear lifting functions. Its horizontal swing characteristics allow the clamping foot to move laterally when not in operation, providing unobstructed operating space for workpiece placement. The adjustable angle design of the second clamping arm through the bolt connection can accurately adapt to the clamping position of workpieces of different specifications. The hydraulic swing cylinder drives the second clamping arm to automatically complete the continuous actions of avoidance, positioning, and pressing down. After the worker places the workpiece, the clamping can be completed by triggering with one hand, eliminating the safety risks of traditional two-hand operation and improving clamping efficiency.

[0032] 4. This utility model utilizes the hollow structure of the crossbar itself to establish an axial heat dissipation channel, with compressed airflow passing through the cavity to carry away the welding heat. This directly intervenes in the heat conduction path, suppressing thermal expansion and deformation of the crossbar from the source, reducing vertical bar positional shifts caused by thermal stress, and improving the geometric accuracy and stability of the product.

[0033] 5. The cross-patterned knurling on the surface of this utility model increases the coefficient of friction with the workpiece contact surface, providing reliable anti-slip protection when the rotating platform rotates at high speed. The workpiece remains stable during welding, avoiding misalignment of the weld finish due to micro-slippage, reducing the repair rate and improving the weld appearance quality. Elastic protrusions create a localized interference fit, generating instantaneous holding force when the vertical rod contacts the positioning block. Non-contact magnetic pre-positioning allows the workpiece to automatically adhere to an approximate design position when placed in the fixture. The worker only needs to gently push with one hand to complete the final positioning, avoiding the complexity of simultaneous micro-adjustment with both hands. This significantly reduces the difficulty of training new operators while improving the consistency of the clamping rhythm for multiple workpieces.

[0034] Other advantages, objectives and features of this invention will be partly apparent from the following description, and partly understood by those skilled in the art through study and practice of this invention. Attached Figure Description

[0035] Figure 1 This is a top view of the rotating platform welding device for table legs according to the present invention.

[0036] Figure 2 This is a front structural schematic diagram of the rotating platform welding device for table legs according to the present invention;

[0037] Figure 3 This is a top view of the rotating platform of this utility model.

[0038] Figure 4 This is a front structural diagram of the rotating platform of this utility model;

[0039] Figure 5 This is a schematic diagram of the structure of the table leg of this utility model.

[0040] The components include: welding machine 10, Y-axis module 101, X-axis linear module 102, Z-axis module 103, extension arm 104, welding torch 105, R-axis rotating wrist 106, rotating platform 20, seat plate 21, U-shaped groove 201, vertical rod positioning block 202, horizontal rod positioning block 203, horizontal rod reference block 204, horizontal adjustment mechanism 205, horizontal rod positioning groove 206, second permanent magnet group 207, elastic protrusion 208, vertical reference surface 240, airflow channel 241, air inlet 242, table leg 30, horizontal rod 301, vertical rod 302, welding part 303, clamping mechanism 40, hydraulic swing cylinder 401, first clamping arm 402, bolt connector 403, second clamping arm 404, clamping foot 405, pressure head 406, and rotating bearing 50. Detailed Implementation

[0041] The present invention will be further described in detail below with reference to the embodiments, so that those skilled in the art can implement it based on the description.

[0042] As shown in Figures 1-5, a rotating platform welding device for table legs is provided. As shown in Figure 5, the table leg 30 consists of a horizontal bar 301 and two vertical bars 302 symmetrically welded on the same side of the horizontal bar. The joint between the horizontal bar and the vertical bar is the welding part. In order to complete the welding operation of the welding part, as shown in Figure 1, the device includes a welding machine 10 and a rotating platform 20.

[0043] The rotating platform 20 is mounted on the side of the base of the welding machine 10 via a rotating bearing 50. In a commonly used rotating structure, the rotating bearing 50 can be a crossed roller bearing. The outer ring of the crossed roller bearing is bolted to the base frame of the welding machine 10, and the inner ring is welded to the base plate of the rotating platform 20. A worm gear reducer is mounted on the base plate. The worm gear is keyed to the spindle of the rotating platform 20, and the input end of the worm gear is connected to a servo motor. The servo motor can be a flange-mounted type, directly connected to the worm gear via a coupling. The base plate 21 of the rotating platform 20 is made of steel plate, with a thickness of 30mm being optional. As shown in Figure 1, when the base plate 21 is not flipped up, its front side faces upward, serving as the workpiece support surface. In the illustration, a U-shaped groove 201 extending inward is provided on the left edge of the seat plate 21. After the horizontal bar 301 and the vertical bar 302 are installed in the work position, the outline of the U-shaped groove 201 surrounds the joint of the horizontal bar 301 and the vertical bar 302. The joint is the part to be welded, i.e., the welding part 303. After the table leg 30 is fixed, its welding part 303 is exposed 360° around its circumference. After the rotating platform 20 rotates, the welding part of the bottom or side of the workpiece can be opened to the welding machine 10, which facilitates the welding operation. It is not necessary to change the surface of the horizontal bar 301 and the vertical bar 302 separately or to lower the welding machine to the bottom for welding, thus improving efficiency.

[0044] The crossbar positioning groove 206 is set on the upper surface of the base plate 21 by welding or bolt fixing. In an optional embodiment, the crossbar positioning groove 206 is formed on the crossbar positioning block 203, which is fixed to the base plate 21 by welding or bolting. The groove width is about 0.8mm larger than the diameter of the crossbar 301, and the groove depth can be selected as 20mm. The vertical bar positioning block 202 is installed on the base plate 21 corresponding to the position of the vertical bar 302. In the illustration, a pair of vertical bar positioning blocks 202 are set as a group, located on the left and right sides of the vertical bar 302 respectively, limiting the vertical bar 302. Each vertical bar 302 is provided with two sets of vertical bar positioning blocks 202. The vertical bar positioning blocks 202 can be fastened by countersunk bolts or directly welded.

[0045] The fixed part is a horizontally swinging upper and lower clamping mechanism 40. In one embodiment, a hydraulic swing cylinder 401 with integrated rotation and lifting functions can be used as the clamping mechanism 40. The hydraulic swing cylinder 401 is vertically mounted on the workpiece support surface at the edge of the seat plate 21 by four sets of bolts, and its output shaft has dual degrees of freedom of synchronous rotation and linear lifting. The lower end of the first clamping arm 402 is rigidly connected to the output shaft of the hydraulic swing cylinder through a flange and is secured with a lock nut, so that the first clamping arm 402 can rotate and lift synchronously with the output shaft. The second clamping arm 404 is connected to the upper end of the first clamping arm 402 through a bolted connector 403. The bolted connector has an elongated hole design, which allows the included angle between the two arms to be adjusted within the range of 0°-30° to adapt to the clamping position of workpieces of different specifications. The end of the second clamping arm 404 is threaded and equipped with a downwardly extending detachable clamping foot 405. The bottom of the foot can be replaced with a knurled pressure head 406 of different specifications.

[0046] During operation, when the table legs are not in place, the hydraulic swing cylinder drives the second clamping arm 404 to swing laterally by 60° to the clearance position; after the workpiece is placed and positioned, the hydraulic swing cylinder simultaneously performs two actions: driving the second clamping arm 404 to rotate horizontally to 0° to directly above the crossbar, and simultaneously pushing the clamping foot 405 down to the set pressure, such as the 20~500N pressure sensor feedback value, to realize a fully automatic clamping process under single mechanism control.

[0047] The welding machine 10 can be a commonly used four-axis welding robot, comprising X / Y / Z three-axis linear modules and an R-axis rotary wrist 106. In one example, as shown in Figures 1 and 2, the X-axis linear module 102 is fixed to the top surface of the welding machine 10's base by anchor bolts, with a selectable stroke of 1500 mm; the Y-axis module 101 is vertically mounted on the slider of the X-axis linear module 102, with a selectable stroke of 800 mm; the Z-axis module 103 is fixed to the slider of the Y-axis module 101, with a selectable stroke of 500 mm. The R-axis rotary wrist 106 is mounted on the Z-axis module 103, with a swing range of ±180°. The welding torch 105 is clamped at the end of the R-axis by an extension arm 104, enabling multi-position welding in space. When setting the welding motion trajectory of the welding robot, attention should be paid to ensuring that the minimum gap between the edge of the U-shaped groove 201 and the motion envelope of the welding torch 105 is 15mm to prevent the welding torch 105 from colliding with the edge of the groove.

[0048] In one working process, the operator places the horizontal bar 301 into the positioning slot 206, and the vertical bar 302 is pressed against the positioning block 202. The connection between the horizontal bar 301 and the vertical bar 302 forms the welding area 303. Pressing the control button, the swing motor 403 drives the second clamping arm 404 to rotate 90° to directly above the horizontal bar 301. The drive cylinder 401 pushes the pressure foot 405 down to the set position, such as when the pressure sensor feedback value reaches 500N. The welding robot moves along the preset path to the entrance of the U-shaped groove 201, the rotating platform 20 rotates at a uniform speed of 2 r / min, and the welding torch 105 simultaneously performs circumferential welding. After welding is completed, the cylinder lifts the pressure foot 405, and the swing motor 403 returns to the clearance position, at which point the workpiece can be removed.

[0049] This implementation method offers good structural stability and low manufacturing cost. The motion coordination between the rotating platform 20 and the welding robot is achieved through PLC programming, resulting in high position synchronization accuracy and meeting the welding process requirements for continuous circumferential seams.

[0050] Before adopting the above-mentioned improved solution, a fixed welding fixture platform was used. This platform consisted entirely of a steel plate worktable, with the workpiece fixed to it. It lacked rotation capability and employed an upper-pressure bolt locking mechanism. The positioning blocks partially surrounded the welding area, leaving only a top operating window. In contrast, this proposed solution features a side-opening U-shaped groove, allowing the welding torch 105 to enter the bottom of the joint horizontally. This eliminates the obstruction of the bottom by traditional fixtures. The workpiece is driven to rotate via the rotating platform 20, and the welding torch 105 simultaneously performs circumferential welding. Only one workpiece clamping is required, avoiding the need for manual workpiece changing required in traditional fixed welding, thus improving efficiency.

[0051] In another embodiment, a crossbar reference block 204 is provided on the base plate 21, and a vertical reference surface 240 is formed on the side facing the end of the crossbar 301. The crossbar reference block 204 is mounted on the base plate 21 via a lateral adjustment mechanism 205 and can slide along the length of the base plate 21. The end face of the crossbar 301 abuts against the vertical reference surface 240, defining the axial position of the crossbar 301.

[0052] The crossbar reference block 204 is a machined steel part with dimensions of 80mm (length) × 50mm (width) × 40mm (height). The vertical reference surface 240 can be further smoothed, with a surface roughness controlled to Ra≤3.2μm to ensure a tight fit with the end face of the crossbar 301. This reference block is fixed to the slider of the transverse adjustment mechanism 205 by four sets of M8 countersunk bolts. The installation position can be selected at the end of the base plate 21 along its length, approximately 50mm from the end face of the crossbar positioning groove 206, to avoid interfering with workpiece placement. The transverse adjustment mechanism 205 can be a linear guide pair, including a 25mm wide ball linear guide and a matching slider. The guide is fixed to the T-slot on the upper surface of the base plate 21 by M6 socket head cap screws, and parallelism must be calibrated during installation. The slider stroke can be set to 200-400mm, covering common crossbar 301 length specifications. A threaded hole is machined on the top of the slider to connect the crossbar reference block 204, and a butterfly locking bolt is added on the side to lock the position when tightened.

[0053] In one working process, the wing bolt is loosened, and the crossbar reference block 204 is pushed along the guide rail to the scale mark (e.g., 300mm). The wing bolt is then tightened, and the crossbar 301 is placed into the positioning groove 206. It is then pushed along the groove until the end face is flush with the vertical reference surface 240, thereby reducing the axial positioning error of the crossbar 301. Compared to workers using calipers to measure the overhang of the crossbar 301 and manually adjusting its position, this reverse method can effectively improve the speed of vertical assembly of the crossbar 301, avoid asymmetrical welding of the vertical bar 302, and improve the repeatability accuracy of batch production.

[0054] In another embodiment, the clamping mechanism 40 uses a hydraulic swing cylinder as an integrated drive unit. This hydraulic swing cylinder is vertically fixed to the edge of the base plate 21 by four sets of M8 bolts, and its output shaft has synchronous rotation and linear lifting functions. The first clamping arm 402 can be made of 40×40mm square steel, with a length selectable from 20 to 100mm. A welded flange at the lower end is rigidly connected to the output shaft of the hydraulic swing cylinder, enabling the first clamping arm 402 to synchronously perform a combined rotation and lifting motion. The second clamping arm 404 is connected to one end of the first clamping arm 402 via a bolt connector 403 with an elongated hole. This structure allows adjustment of the angle between the two arms within a range of approximately ±15°. The end of the second clamping arm 404 is equipped with a clamping foot 405, and the bottom of the foot can be detachably replaced with a knurled pressure head 406.

[0055] In one working process, the hydraulic swing cylinder drives the second clamping arm 404 to swing laterally to a 60° clearance position, away from the center of the workpiece placement area. After the workpiece is positioned, the hydraulic swing cylinder simultaneously performs the following: the horizontal rotation of the output shaft causes the second clamping arm 404 to swing to 0°, reaching directly above the crossbar 301, and simultaneously pushes the output shaft down a stroke of 10~150mm, causing the clamping foot 405 to clamp the workpiece. Compared to the method of clamping the workpiece by holding it down with one hand and tightening the nut with the other, the clearance of the second clamping arm 404 in this embodiment allows the worker to quickly load the workpiece, improving efficiency. Automated clamping eliminates uneven force application by humans, stabilizes the clamping force, and reduces workpiece displacement.

[0056] In another embodiment, both the horizontal bar 301 and the vertical bar 302 are conventional hollow steel pipe structures. An axially penetrating airflow channel 241 is formed inside the horizontal bar reference block 204. One end of the airflow channel 241 has an air inlet 242 located at the end of the reference block facing away from the vertical reference surface 240, connected to an external compressed air source. An air outlet group is formed on the vertical reference surface 240, directly opposite the hollow inner cavity at the end of the horizontal bar 301, forming an axial heat dissipation channel.

[0057] The airflow channel 241 can be a Φ6mm through hole, axially drilled inside the crossbar reference block 204. The air inlet 242 uses a G1 / 4 quick-connect coupling, screwed into the center of the reference block end face via an M10×1 thread, and connected to the compressed air system via an external hose. The air outlet group consists of three evenly distributed Φ2mm holes, 10mm apart, arranged in a triangle on the vertical reference plane 240. The compressed air pressure is set to 0.3MPa via a pressure regulating valve, and the flow rate is monitored by a flow meter in the range of 8-10L / min. The air circuit system can be configured with a solenoid valve to control its start and stop, opening synchronously when welding begins. In this embodiment, the airflow directly penetrates the crossbar 301 cavity, forming forced convection inside the crossbar 301, which can effectively dissipate heat and prevent local high-temperature deformation and displacement caused by welding.

[0058] In another embodiment, a knurled pressure head 406 is embedded at the bottom of the clamping foot 405. The knurled pressure head 406 has a surface texture depth of 0.2mm and a texture angle of 90°. The knurling head can be formed using a common CNC rolling process to create a cross-shaped diamond pattern with a texture depth of 0.2mm and an angle of 90°±1° between adjacent patterns. This commonly used knurling head is used here to effectively clamp the smooth surface of the horizontal bar 301 and vertical bar 302 workpiece. It is inexpensive, durable, and easy to replace, making it very suitable for workpieces in frequent contact conditions. The knurled tip is screwed into the threaded hole at the end of the clamping foot 405. After assembly, the working surface of the pressure head 406 protrudes from the base of the clamping foot 405, ensuring that the textured area is in complete contact with the workpiece surface.

[0059] In another embodiment, the side of the vertical rod positioning block 202 is provided with elastic protrusions 208, the protrusion height of which is 0.5-1mm, for forming an interference fit with the side of the vertical rod 302. The elastic protrusions 208 can be molded from polyurethane rubber. A blind hole with a depth of 6mm is drilled on the side of the positioning block, and the elastic protrusions 208 are fixed in the blind hole with cyanoacrylate adhesive. After curing, the protrusion height is about 0.75mm. Each positioning block can be arranged with two rows of six protrusions. After assembly, the axis of the elastic protrusions 208 is perpendicular to the abutment surface of the vertical rod 302 and more than 25mm away from the edge of the part to be welded 303. When the workpiece is loaded, the vertical rod 302 compresses the elastic protrusions 208 to produce compression deformation, resulting in an interference fit and pre-tightening, preventing workpiece displacement caused by vibration, and allowing the worker to quickly complete the clamping.

[0060] In another embodiment, a first permanent magnet group is provided below the bottom of the horizontal bar positioning groove 206; a second permanent magnet group 207 is embedded in the abutment surface of the vertical bar 302 of the vertical bar positioning block 202, and the surface of the second permanent magnet group 207 is 0.5-1mm lower than the abutment surface; the permanent magnet group is ≥20mm away from the nearest welding part 303; the first permanent magnet group and the second permanent magnet group 207 have non-contact magnetic attraction with the horizontal bar 301 and the vertical bar 302 respectively, for magnetic pre-positioning when the workpiece is placed.

[0061] The first permanent magnet assembly can be made of neodymium iron boron permanent magnets, which can be bonded or embedded in the bottom surface of the crossbar positioning groove 206 or set at the bottom of the crossbar positioning block (the installation position can be adjusted as needed, as long as it can attract the crossbar 301). The second permanent magnet assembly 207 uses magnets of the same specification and is embedded in the vertical contact surface of the vertical bar positioning block 202 on the base plate 21, with the magnet surface about 0.8mm lower than the contact surface. It should be noted that the permanent magnet assembly should be ≥20mm, such as 25mm, from the edge of the part to be welded 303 to reduce the impact on welding.

[0062] When loading a workpiece, the workpiece needs to be precisely aligned with the positioning groove 206 and the positioning block 202. Vibration can easily cause deviation, which requires adjustment and is time-consuming. The permanent magnet assembly in this embodiment can assist in workpiece positioning and improve loading speed and accuracy.

[0063] Although the embodiments of this utility model have been disclosed above, they are not limited to the applications listed in the specification and embodiments. It can be applied to various fields suitable for this utility model. Other modifications can be easily made by those skilled in the art.

Claims

1. A rotating platform welding device for table legs, wherein the table leg is composed of a horizontal bar and two vertical bars symmetrically welded on the same side of the horizontal bar, characterized in that, Including welding machines and rotating platforms; The rotating platform is rotatably connected to the welding machine, and the rotating platform includes: The base plate, the top surface of which serves as the workpiece support surface; The positioning part includes a horizontal bar positioning groove and two vertical bar positioning blocks on the seat plate; the horizontal bar positioning groove is located in the length direction of the seat plate and the groove opening matches the shape of the bottom surface of the horizontal bar; several vertical bar positioning blocks are arranged side by side on the same side of the horizontal bar positioning groove and respectively abut against and limit the movement of the sides of the two vertical bars. The fixing part is a horizontally swingable and height-adjustable clamping mechanism, which is set on the seat plate and is used to clamp the table legs downwards to the horizontal bar positioning groove and the vertical bar positioning block; The seat plate has a U-shaped groove extending inward from the edge. The outline of the U-shaped groove surrounds the joint between the horizontal and vertical bars, so that the welded parts of the table legs are exposed 360° around the circumference after they are fixed.

2. The rotary platform welding device according to claim 1, characterized in that, The seat plate is also provided with a crossbar reference block, which is installed on the seat plate by a lateral adjustment mechanism and is located at the end of the crossbar; the side of the crossbar reference block facing the end of the crossbar forms a vertical reference surface, which is used to abut against the end face of the crossbar to define the position of the crossbar in the length direction.

3. The rotary platform welding apparatus according to claim 1 or 2, characterized in that, The tightening mechanism includes: The hydraulic swing cylinder is vertically fixed to the workpiece support surface of the base plate, and its output shaft has the functions of synchronous rotation and linear lifting. The first clamping arm has its first end rigidly connected to the output shaft of the hydraulic swing cylinder so that it can be driven by the hydraulic swing cylinder to perform simultaneous rotation and lifting movements. The second clamping arm is connected to the second end of the first clamping arm by a bolted connector, and the bolted connector allows adjustment of the included angle between the second clamping arm and the first clamping arm to adjust the support position at its end; the end of the second clamping arm is provided with a downwardly extending clamping foot. When the table leg is not in the positioning part, the hydraulic swing cylinder drives the second clamping arm to swing laterally to the clearance position; after the table leg is positioned, the hydraulic swing cylinder drives the second clamping arm to swing directly above the crossbar, and simultaneously drives the clamping foot to press down to clamp the table leg.

4. The rotary platform welding device according to claim 2, characterized in that, The crossbar reference block has an axially penetrating airflow channel inside, which includes: The air intake port is located at the end of the crossbar reference block facing away from the vertical reference plane, and is connected to an external compressed air source. The air vent assembly is located on the vertical reference plane and is directly opposite the hollow inner cavity at the end of the crossbar. When the end face of the crossbar abuts against the vertical reference plane, the air outlet group connects with the hollow inner cavity of the crossbar to form an axial heat dissipation channel.

5. The rotary platform welding apparatus according to claim 3, characterized in that, The bottom of the presser foot is fitted with a knurled presser head.

6. The rotary platform welding apparatus according to claim 1, characterized in that, The side of the vertical rod positioning block is provided with elastic protrusions, the protrusion height of which is 0.5-1mm, which are used to form an interference fit with the side of the vertical rod.

7. The rotary platform welding apparatus according to claim 1, characterized in that, The bottom of the horizontal bar positioning groove is provided with a first permanent magnet group; the vertical bar abutment surface of the vertical bar positioning block is embedded with a second permanent magnet group, the surface of the second permanent magnet group is 0.5-1mm lower than the abutment surface; the permanent magnet group is ≥20mm away from the nearest part to be welded; The first and second permanent magnet groups interact with the horizontal and vertical bars respectively through non-contact magnetic attraction, which is used for magnetic pre-positioning when placing the workpiece.

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