Hydraulic press with toggle mechanism for metal piece processing

Abstract

The present application relates to metal piece processing equipment technical field, specifically for a kind of metal piece processing with toggle mechanism's hydraulic machine, including workbench, fixedly arranged lower die seat on workbench, fixedly arranged top frame above lower die seat, vertical column is connected between top frame and workbench, and main hydraulic cylinder is installed on top frame, the output end of the main hydraulic cylinder is drivingly connected with movable die seat, drives movable die seat to vertically lift and slide along vertical column, the center of the lower die seat is fixed with center die.The present application is driven to the center by vertical toggle mechanism by movable die seat down pressure, cooperates with the arc clamping surface of follow-up clamp block to form envelope positioning to pipe fitting, can effectively inhibit axial migration and circumferential deflection of pipe fitting in bending process;When toggle connecting rod tends to horizontal dead point, into pressure maintaining state, cooperates with the elastic compensation of buffer spring assembly, can offset the pressure attenuation caused by abrasion at hinge, avoid pipe fitting surface clamp injury while guarantee bending position precision.

Description

Technical Field

[0001] This invention relates to the field of metal processing equipment technology, and in particular to a hydraulic press with a toggle mechanism for metal processing. Background Technology

[0002] In the U-bending and pressure bending processes of metal round tubes and irregularly shaped pipe fittings, hydraulic presses are widely used in the pipe fitting processing of hardware, auto parts, and construction machinery industries due to their advantages of stable pressure output and controllable forming accuracy. A conventional pipe bending hydraulic press mainly consists of a worktable, frame, main hydraulic cylinder, forming pressure head, and lower die. The main hydraulic cylinder drives the pressure head to descend vertically, pressing the pipe fitting into the lower die cavity to complete the bending deformation.

[0003] Regarding the processing accuracy and forming quality of pipe bending, existing technologies mainly have the following shortcomings: 1. Insufficient lateral positioning capability and redundant clamping scheme: During bending, smooth round tubes and polished pipe fittings are prone to axial movement and circumferential deflection due to radial force, leading to bending position deviation and out-of-tolerance forming angle. Existing technologies usually solve this problem by adding independent lateral clamping cylinders. However, independent control of multiple cylinders requires a multi-way directional valve and a synchronous control system, which not only increases equipment costs and complicates hydraulic pipelines, but also makes the timing accuracy of clamping and main pressure actions highly dependent on electrical control debugging. After long-term use, wear of seals and pressure drift can easily cause synchronization delays, resulting in surface damage or clamping failure of the pipe fittings.

[0004] 2. Failure of support for suspended sections leads to frequent forming defects: When bending long pipes, the suspended sections at both ends tend to tilt upwards as the bending angle increases. When using a fixed support structure, the support points gradually detach and misalign with the outer wall of the pipe during the bending process, failing to provide continuous normal support force. Thin-walled pipes are prone to forming defects such as local out-of-roundness and sidewall wrinkling. Some follow-up support structures require additional drive components, which also suffer from poor synchronization and structural redundancy. Furthermore, the support mechanism lacks mechanical locking after bending, and the workpiece's springback can cause the support mechanism to reverse and reset, failing to maintain forming accuracy.

[0005] 3. Low demolding efficiency and poor linkage: After bending and forming, the tubular parts are embedded in the lower mold cavity. Existing technologies mostly use independent ejector cylinders or manual assistance for part removal. Independent ejector devices require additional power units and control logic, increasing equipment costs and potential failure points; manual part removal has low production efficiency and poses operational safety hazards. Some mechanical linkage ejector structures have problems with downward stroke interference and uncontrollable ejection position, and cannot coordinate with the unlocking action of the support mechanism, which can easily cause workpiece misalignment and support mechanism jamming.

[0006] 4. Insufficient stability of toggle clamping: Existing hydraulic equipment that uses toggle mechanism for clamping mostly drives the toggle independently, and cannot use the downward power of the main pressure head to achieve timed clamping; and after the toggle enters the dead point pressure holding stage, there is a lack of elastic compensation structure, and the pressure holding pressure is prone to decay after the connecting rod hinge wears, and the clamping force gradually decreases with the increase of processing times. Summary of the Invention

[0007] The purpose of this invention is to provide a hydraulic press with a toggle mechanism for processing metal parts, so as to solve the problems mentioned in the background art.

[0008] To achieve the above objectives, the present invention provides the following technical solution: a hydraulic press with a toggle mechanism for processing metal parts, comprising a worktable, a lower die base fixedly disposed on the worktable, a top frame fixedly disposed above the lower die base, a guide column vertically connected between the top frame and the worktable, and a main hydraulic cylinder mounted on the top frame. The output end of the main hydraulic cylinder is connected to a movable die base for transmission, driving the movable die base to slide vertically up and down along the guide column. A central die is fixed at the center of the lower die base, and a forming pressure head that cooperates with the central die is installed at the bottom of the movable die base. The movable die base is symmetrically provided with moving die heads on both sides. The vertical toggle mechanism is driven by a downward pressure mechanism, with a follower roller at the top of the mechanism. A linkage arm that moves synchronously with the moving mold base is fixedly connected to one side of the moving mold base. An ejector mechanism that cooperates with the linkage arm is provided inside and below the worktable. During the downward movement of the moving mold base driven by the main hydraulic cylinder, the moving mold base first presses the follower roller to close the vertical toggle mechanism towards the center and clamp the metal tube. Then, the forming head presses the metal tube into the central mold and bends it into shape. During the upward return movement of the moving mold base, the linkage arm pulls the ejector mechanism upward to automatically eject the formed metal tube.

[0009] The vertical toggle mechanism includes a fixed base, a first connecting rod hinged to the fixed base at one end, a second connecting rod hinged to the first connecting rod, and a follower clamping block hinged to the second connecting rod; a rotating seat is connected to the hinge axis of the first connecting rod and the second connecting rod, and an upwardly extending push rod is sleeved on the rotating seat; the follower roller is mounted on the top of the push rod through a connecting seat.

[0010] A buffer spring assembly is also connected in series on the push rod; the bottom of the movable mold base is provided with a flat, straight wall bottom surface for pressing down on the follower roller; when the downward stroke causes the first connecting rod and the second connecting rod to tend to the horizontal straight dead point, the movable mold base continues to descend, and the follower roller slides on the straight wall surface of the movable mold base to maintain the pressure holding and locking state of the follower clamping block.

[0011] The central mold is also symmetrically provided with pipe fitting follow-up support mechanisms on the front and rear sides for supporting the suspended ends of metal pipe fittings; the pipe fitting follow-up support mechanism includes a base, a swing arm, a pin, a support block and a follow-up torsion spring. The base is slidably connected to the workbench, the lower end of the swing arm is locked to the base, and the support block is fixedly set at the top of the swing arm; the follower torsion spring is sleeved on the pin, one end of which acts on the lower mold base and the other end acts on the swing arm, providing the swing arm with a continuous torque to swing towards the central mold, so that the support block always keeps close to the bottom of the metal tube during the bending process.

[0012] A limiting component is fixed on the base. The limiting component is located on the worktable and is used to limit the initial position of the base, thereby limiting the initial opening position of the swing arm as it swings outward. The bottom of the base is rotatably provided with a one-way locking structure, which includes a locking block, a top column, a rotating block and a return torsion spring. The return torsion spring is provided on both sides of the rotating block, and the corresponding position of the base is provided with a slot that cooperates with the locking block. The reset torsion spring normally drives the one-way locking structure to rotate out and engage in the slot, thus locking the position of the swing arm. When the linkage arm moves upward, the top material mechanism presses the rotating block upward, causing it to overcome the torque of the reset torsion spring and rotate to a horizontal state. The upper end disengages from the slot to release the lock. Under the gravity of the metal tube, the swing arm swings outward to reset and abuts against the limiting component.

[0013] The ejector mechanism includes an ejector rod that vertically penetrates the central mold and a bottom crossbeam located at the bottom of the workbench; the lower end of the ejector rod is fixed to the bottom crossbeam, and the lower end of the linkage arm extends to the bottom of the bottom crossbeam and drives the bottom crossbeam to move upward through a hook structure.

[0014] The bottom crossbeam is equipped with multiple sets of elastic locking components; When the moving mold base moves downward, the bottom crossbeam moves downward through multiple sets of elastic locking components; when the moving mold base moves upward, the two ends of the bottom crossbeam are pushed by the hook structure, forcibly pulling up the bottom crossbeam and the top material rod to complete the mechanical demolding.

[0015] The worktable is also provided with a fine-tuning stop mechanism for limiting the initial position of the lower mold base end. The fine-tuning stop mechanism includes a fixed bracket, a horizontal adjusting screw, and a limiting top block.

[0016] The top of the central mold is provided with a U-shaped forming cavity, and the inner side of the follower clamping block facing the central mold is provided with an arc-shaped clamping surface that matches the U-shaped forming cavity, so as to envelop and position the metal pipe during clamping and prevent it from going out of round.

[0017] The buffer spring assembly includes a limiting ring and an elastic rod. One end of the elastic rod is fixedly connected to the follower clamping block, and the other end of the elastic rod is movably connected to the limiting ring. As the moving mold base continues to descend, the limit ring restricts the push rod from rotating freely, the follower roller moves inward, and the elastic rod ensures continuous lateral pressure on the follower clamping block.

[0018] Compared with the prior art, the beneficial effects of the present invention are: 1. Single power source timing linkage simplifies the structure and improves synchronization reliability. This invention uses only the main hydraulic cylinder as the sole active power source. Relying on the vertical reciprocating motion of the moving mold base, and through physical contour interference and pure mechanical transmission, it sequentially completes the lateral clamping, pressure holding and forming, follow-up support, and return ejection actions in a time sequence. Compared to existing multi-cylinder independent control schemes, it eliminates the need for multiple clamping cylinders, directional valve groups, and synchronous control systems, significantly simplifying the hydraulic pipelines and electrical control logic. Simultaneously, it avoids action delays and failures caused by electrical control timing drift and seal wear, significantly improving the synchronization accuracy and operational stability of the mechanical linkage.

[0019] 2. The toggle-type lateral clamping mechanism combines adaptive clamping with dead-point pressure retention. The vertical toggle mechanism is driven to retract towards the center by the downward pressure of the moving mold base. The arc-shaped clamping surface of the follower clamping block forms an envelope positioning of the pipe, which can effectively suppress the axial movement and circumferential deflection of the pipe during bending. When the toggle connecting rod approaches the horizontal dead point, it enters the pressure holding state. With the elastic compensation of the buffer spring assembly, it can offset the pressure attenuation caused by wear at the hinge, continuously maintain a stable clamping force, avoid damage to the surface of the pipe and ensure the bending position accuracy.

[0020] 3. Swing-type follow-up support, providing full-range conformal support and featuring end-locking function. The support structure, which employs a swing arm and a follow-up torsion spring, allows the support block to swing adaptively with the tilting angle of the pipe during bending, always maintaining a normal posture against the outer wall of the pipe to provide continuous support for the suspended section. This effectively avoids forming defects such as sidewall wrinkling and local out-of-roundness when bending thin-walled pipes. After bending to the correct position, the one-way locking structure automatically engages with the base slot under the action of the reset torsion spring to form a mechanical lock, suppressing workpiece springback deformation and maintaining forming accuracy. During the return stroke, the support mechanism automatically resets to the position of the limit component, relying on the upward movement of the linkage arm to unlock synchronously, without the need for additional drive components.

[0021] 4. Return-linkage ejection improves demolding efficiency and operational safety. The linkage arm, which rises and falls synchronously with the moving mold base, along with the bottom crossbeam and one-way elastic locking assembly, achieves a one-way linkage effect of downward free stroke avoidance and upward rigid lifting. The return power of the main hydraulic cylinder automatically completes the ejection and demolding of the workpiece, eliminating the need for a separate ejector cylinder or manual assistance in removing the part. This simplifies the power unit and control links, improves production cycle and operational safety, and the ejection action and the unlocking sequence of the support mechanism are naturally matched, preventing the workpiece from tilting and getting stuck during the ejection process.

[0022] 5. The overall structure is compact and highly adaptable to processing. The machine has a high degree of integration. The toggle mechanism, follow-up support mechanism and ejector mechanism are all symmetrically arranged around the lower mold base, which occupies little space. It can be adapted to the processing of metal pipes with different diameters and bending angles by adjusting the length of the toggle connecting rod and the initial angle of the support swing arm. It has a wide range of applications, and is especially suitable for high-precision bending and forming processes of long thin-walled pipes. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the toggle mechanism in its initial state according to the present invention; Figure 3 This is a schematic diagram of the vertical toggle mechanism in the downward pressing state of the present invention; Figure 4 This is a schematic diagram of the structure in the compressed state of the present invention; Figure 5 This is a schematic diagram of the bending structure of the metal pipe fitting of the present invention; Figure 6 This is a diagram of the pipe fitting follow-up support mechanism of the present invention; Figure 7 This is a diagram of the vertical elbow joint mechanism of the present invention; Figure 8 This is a partial side cross-sectional view of the present invention; Figure 9 This is a schematic diagram of the feeding mechanism of the present invention; Figure 10 This is a schematic diagram of the one-way locking structure of the present invention; Figure 11 This is a schematic diagram of the closed state of the one-way locking structure of the present invention; Figure 12 This is a schematic diagram of the open state of the one-way locking structure of the present invention; Figure 13 This is a schematic diagram of the pressing structure and the ejection and reset structure of the present invention.

[0024] In the diagram: 1. Workbench; 2. Main hydraulic cylinder; 3. Top frame; 4. Guide column; 5. Moving mold base; 6. Linkage arm; 7. Vertical toggle mechanism; 71. Follower roller; 72. Connecting seat; 73. Push rod; 74. Buffer spring assembly; 76. First connecting rod; 77. Second connecting rod; 78. Follower clamping block; 79. Fixed seat; 8. Pipe fitting follower support mechanism; 81. Support block; 82. Swing arm; 83. Support arm; 84. Base; 85. 86. Limiting component; 9. Pin shaft; 10. Forming pressure head; 11. Center mold; 12. Fine adjustment stop mechanism; 13. Lower mold base; 14. Bottom crossbeam; 15. One-way locking structure; 16. Locking block; 17. Top column; 18. Rotating block; 19. Reset torsion spring; 10. Ejector rod; 10. Pressing structure; 11. Pressing column; 12. Spring rod; 13. Ejection and reset structure; 14. Top pressure rod; 15. Lifting plate. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0026] Please see Figures 1-9 A hydraulic press with a toggle mechanism for processing metal parts includes a worktable 1, a lower mold base 12 fixedly mounted on the worktable 1, a top frame 3 fixedly mounted above the lower mold base 12, a guide column 4 vertically connected between the top frame 3 and the worktable 1, and a main hydraulic cylinder 2 mounted on the top frame 3. The output end of the main hydraulic cylinder 2 is connected to a movable mold base 5 for transmission, driving the movable mold base 5 to slide vertically up and down along the guide column 4. A center mold 10 is fixed at the center of the lower mold base 12, and a forming pressure head 9 that is directly opposite to and cooperates with the center mold 10 is installed at the bottom of the movable mold base 5. The center mold 10 is symmetrically provided with vertical toggle mechanisms 7 driven by the downward pressure of the movable mold base 5 on both sides. The top of the vertical toggle mechanism 7 is provided with a follower roller 71. A linkage arm 6 that moves synchronously with the movable mold base 5 is fixedly connected to one side, and a material ejection mechanism that cooperates with the linkage arm 6 is provided inside and below the worktable 1. During the downward movement of the main hydraulic cylinder 2 driving the moving mold base 5, the moving mold base 5 first presses the follower roller 71 to make the vertical toggle mechanism 7 close towards the center to clamp the metal tube. Then the forming head 9 presses the metal tube into the central mold 10 to bend and form it. During the upward return of the moving mold base 5, the linkage arm 6 pulls the ejector mechanism upward to automatically eject the formed metal tube.

[0027] See attached document Figure 2 , Figure 4 , Figure 5 and Figure 7The vertical toggle mechanism 7 includes a fixed base 79, a first connecting rod 76 with one end hinged to the fixed base 79, a second connecting rod 77 hinged to the first connecting rod 76, and a follower clamping block 78 hinged to the second connecting rod 77; a rotating seat 75 is connected at the hinge axis of the first connecting rod 76 and the second connecting rod 77, and a push rod 73 extending upward is sleeved on the rotating seat 75. The follower roller 71 is mounted on the top of the push rod 73 through a connecting seat 72.

[0028] A buffer spring assembly 74 is also connected in series on the push rod 73; the bottom of the movable mold base 5 is provided with a flat straight wall bottom surface for pressing down the follower roller 71; when the downward stroke causes the first connecting rod 76 and the second connecting rod 77 to tend to the horizontal straight dead point, the movable mold base 5 continues to move downward, and the follower roller 71 slides on the straight wall surface of the movable mold base 5 to maintain the pressure holding and locking state of the follower clamping block 78. A pressing structure 16 is provided on one side of the follower clamping block 78. The pressing structure 16 includes a pressing column 161 provided on one side of the follower clamping block 78 and a spring rod 162 connected to one side of the pressing column 161. As the follower clamping block 78 approaches the center mold 10, one end of the pressing column 161 presses against the side of the metal tube. As the metal tube bends and moves downward, the spring rod 162 returns to the initial position when one end of the pressing column 161 is removed from the metal tube.

[0029] The buffer spring assembly 74 includes a limiting ring 742 and an elastic rod 741. One end of the elastic rod 741 is fixedly connected to the follower clamp 78, and the other end of the elastic rod 741 is movably connected to the limiting ring 742. The limiting ring 742 is sleeved on the push rod 73. As the moving mold base 5 continues to descend, the limiting ring 742 restricts the push rod 73 from rotating freely, the follower roller 71 moves inward, and the elastic rod 741 ensures continuous lateral pressure on the follower clamp 78.

[0030] Reference Figure 6 The central mold 10 is also symmetrically provided with pipe fitting follow-up support mechanism 8 for supporting the suspended end of the metal pipe fitting on both the front and rear sides; the pipe fitting follow-up support mechanism 8 includes a base 84, a support arm 83, a swing arm 82, a pin 86, a support block 81 and a follow-up torsion spring. The base 84 is slidably connected to the worktable 1, and the lower end of the support arm 83 is fixedly connected to the base 84. The support arm 83 and the base 84 are relatively fixed, which can ensure that the end of the support arm 83 can be normally transmitted to the base 84 after being subjected to the force of the swing arm 82, so that the base 84 can slide normally under force. The upper end of the support arm 83 is slidably connected to the swing arm 82, the support block 81 is fixedly set at the top of the swing arm 82, the pin 86 is connected to the bottom end of the swing arm 82, and the two ends of the pin 86 are rotatably connected to the lower mold base 12; the follower torsion spring is sleeved on the pin 86, one end of which acts on the lower mold base 12 and the other end acts on the swing arm 82, providing the swing arm 82 with a continuous torque to swing towards the center mold 10, so that the support block 81 always keeps close to the bottom of the metal tube during the bending process.

[0031] A limiting member 85 is fixed on the base 84. The limiting member 85 is located on the worktable 1 and is used to limit the initial position of the base 84, thereby limiting the initial opening position of the swing arm 82 swinging outward. Reference Figures 9-13 The bottom of the base 84 is rotatably provided with a one-way locking structure 14. The one-way locking structure 14 includes a locking block 141, a top post 142, a rotating block 143 and a reset torsion spring 144. The reset torsion spring 144 is located on both sides of the rotating block 143. The corresponding position of the base 84 is provided with a slot that cooperates with the locking block 141. Under normal conditions, the reset torsion spring 144 drives the one-way locking structure 14 to rotate out and engage in the slot, thus locking the position of the swing arm 82. When the linkage arm 6 moves upward, it pushes the rotating block 143 upward through the top material mechanism, causing it to overcome the torque of the reset torsion spring and rotate to a horizontal state. The upper end disengages from the slot to release the lock. Under the gravity of the metal pipe, the swing arm 82 swings outward to reset and abuts against the limiting member 85.

[0032] In this embodiment, as a preferred option, the ejector mechanism includes an ejector rod 15 that vertically penetrates the central mold 10, and a bottom crossbeam 13 disposed at the bottom of the workbench 1; the lower end of the ejector rod 15 is fixed to the bottom crossbeam 13, and the lower end of the linkage arm 6 extends to the bottom of the bottom crossbeam 13 and drives the bottom crossbeam 13 to move upward through the hook structure.

[0033] In this embodiment, as a preferred option, the bottom crossbeam 13 is provided with multiple sets of elastic locking components; When the moving mold base 5 moves downward, the bottom crossbeam 13 moves downward through multiple sets of elastic locking components; when the moving mold base 5 moves upward, the two ends of the bottom crossbeam 13 are pushed by the hook structure to forcibly pull up the bottom crossbeam 13 and the ejector rod 15 to complete mechanical demolding; the bottom crossbeam 13 is provided with ejection reset structure 17 on both sides. The ejection reset structure 17 includes an ejector rod 171 and a lifting plate 172. The lifting plate 172 is connected to the bottom crossbeam 13. The lower end of the ejector rod 171 is connected to the lifting plate 172, and its upper end presses against the vertical toggle mechanism 7. As the moving mold base 5 moves upward to the top, the ejector rod 171 opens and unlocks the vertical toggle mechanism 7, causing the follower clamp 78 to move to one side.

[0034] In this embodiment, as a preferred option, the workbench 1 is also provided with a fine-tuning stop mechanism 11 for limiting the initial position of the end of the lower mold base 12. The fine-tuning stop mechanism 11 includes a fixed bracket, a horizontal adjusting screw, and a limiting top block.

[0035] In this embodiment, as a preferred option, the top of the central mold 10 is provided with a U-shaped forming cavity, and the follower clamping block 78 is provided with an arc-shaped clamping surface that matches the U-shaped forming cavity on the inner side of the central mold 10, so as to envelop and position the metal pipe during clamping and prevent it from becoming out of round.

[0036] In the initial state, the movable mold base 5 is at its highest point, the vertical toggle mechanism 7 is in a bent state, the base 84 of the pipe fitting follow-up support mechanism 8 is far away from the limiting member 85, the one-way locking structure 14 is in a closed state, and the top surface of the ejector rod 15 protrudes from the bottom surface of the mold cavity of the central mold 10.

[0037] The metal pipe to be processed is placed in the U-shaped groove of the support block 81. The end of the pipe is supported by its own weight, which unfolds the pipe follower support mechanism 8. Here, the swing arm 82 is subjected to the radial tension of the follower torsion spring and the gravity from the downward pressure of the metal pipe. The gravity here is greater than the upward force of the radial tension of the follower torsion spring, so the swing arm 82 rotates. The support block 81 slides along the metal pipe to its end, so that the base 84 slides outward and abuts against the limiting member 85. The main hydraulic cylinder 2 drives the moving mold base 5 to move downward along the guide post 4. First, the bottom surface of the movable mold base 5 contacts the follower roller 71, pushing the push rod 73 to move down. The first connecting rod 76 and the second connecting rod 77 gradually unfold, causing the follower clamping blocks 78 on both sides to retract towards the center. Under the limiting action of the limit slide groove at the bottom of the follower clamping block 78, the follower clamping block 78 gets infinitely close to the metal pipe without contacting it, clamping the metal pipe from both sides. As it continues downward, the forming head 9 contacts the middle of the tube and begins to press the tube into the U-shaped cavity of the center mold 10; the two ends of the tube are forced to tilt upward, causing the swing arm 82 to swing inward and upward around the pin 86, and the follow-up torsion spring continues to apply pressure, so that the support block 81 is always in close contact with the bottom of the tube, providing normal support and preventing the side wall from wrinkling and becoming out of round. When the first link 76 and the second link 77 approach the horizontal dead point, the clamping force increases sharply and enters the pressure holding state; the moving mold base 5 continues to move downward, the follower roller 71 rolls along the bottom surface, and the buffer spring assembly 74 is compressed to compensate and maintain a stable clamping force; When the bend is in place, the one-way locking structure 14 engages with the slot of the base 84, locking the position of the swing arm 82 and suppressing the springback of the tube. During the entire downward movement, the linkage arm 6 moves down synchronously with the downward movement of the moving mold base 5. The bottom crossbeam 13 loses its support and moves downward. At this time, the top surface of the ejector rod 15 is flush with the bottom surface of the mold cavity of the center mold 10, and the one-way locking structure 14 is not subjected to the pressure below, thus achieving rotation. Due to the elastic effect of the ejector pin 142, when the base 84 moves towards the lower mold base 12, it can press down and pass the locking block 141.

[0038] After the bending and pressure holding are completed, the main hydraulic cylinder 2 drives the moving mold base 5 to move upwards for the return stroke: In the initial stage of the upward movement of the moving mold base 5, the pressure of the follower roller 71 is gradually released, the toggle link begins to retract, and the clamping force gradually decreases. The moving mold base 5 continues to move upward. Under the traction of the linkage arm 6, the bottom crossbeam 13 drives the bottom crossbeam 13 and the ejector rod 15 to rise, ejecting the molded tube from the mold cavity and completing the automatic demolding. As the bottom crossbeam 13 pushes the one-way locking structure 14 upward, it forces the one-way locking structure 14 to rotate, causing the ejector pin 142 to move downward and the locking block 141 to rotate downward and disengage from the slot under the base 84, so that the base 84 is in the unlocked state. After the moving mold base 5 returns to the top dead center, the workpiece is removed, a new pipe to be processed is placed in, and the next work cycle begins.

[0039] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A hydraulic press with a toggle mechanism for processing metal parts, comprising a worktable (1), a lower die base (12) fixedly disposed on the worktable (1), a top frame (3) fixedly disposed above the lower die base (12), a guide column (4) vertically connected between the top frame (3) and the worktable (1), and a main hydraulic cylinder (2) mounted on the top frame (3), wherein the output end of the main hydraulic cylinder (2) is connected to a movable die base (5) for transmission, driving the movable die base (5) to slide vertically up and down along the guide column (4), characterized in that: The lower mold base (12) has a central mold (10) fixed at its center, and the bottom of the movable mold base (5) is equipped with a forming pressure head (9) that is directly opposite to the central mold (10). The central mold (10) is symmetrically provided with vertical toggle mechanisms (7) driven by the downward pressure of the movable mold base (5) on both sides, and the top of the vertical toggle mechanism (7) is provided with a follower roller (71). The movable mold base (5) is fixedly connected to one side with a linkage arm (6) that moves up and down synchronously with it. The workbench (1) is provided with a material ejection mechanism that cooperates with the linkage arm (6) inside and below. During the process of the main hydraulic cylinder (2) driving the moving mold base (5) downward, the moving mold base (5) first presses the follower roller (71) so that the vertical toggle mechanism (7) closes and clamps the metal tube towards the center. Then the forming head (9) presses the metal tube into the central mold (10) and bends it into shape. During the process of the moving mold base (5) moving upward and returning, the linkage arm (6) pulls the ejector mechanism upward to automatically eject the formed metal tube.

2. The hydraulic press with a toggle mechanism for processing metal parts according to claim 1, characterized in that, The vertical toggle mechanism (7) includes a fixed seat (79), a first connecting rod (76) hinged at one end to the fixed seat (79), a second connecting rod (77) hinged to the first connecting rod (76), and a follower clamp (78) hinged to the second connecting rod (77); a rotating seat (75) is connected at the hinge axis of the first connecting rod (76) and the second connecting rod (77), and the rotating seat (75) is sleeved with an upwardly extending push rod (73), and the follower roller (71) is mounted on the top of the push rod (73) through a connecting seat (72).

3. The hydraulic press with a toggle mechanism for processing metal parts according to claim 2, characterized in that, A buffer spring assembly (74) is also connected in series on the push rod (73); the bottom of the movable mold base (5) is provided with a flat, straight wall bottom surface for pressing down the follower roller (71); when the downward stroke causes the first connecting rod (76) and the second connecting rod (77) to tend to the horizontal straight dead point, the movable mold base (5) continues to move downward, and the follower roller (71) slides on the straight wall surface of the movable mold base (5) to maintain the pressure-holding and locking state of the follower clamp (78). A pressing structure (16) is provided on one side. The pressing structure (16) includes a pressing column (161) provided on one side of the follower clamp (78) and a spring rod (162) connected to one side of the pressing column (161). As the follower clamp (78) approaches the center mold (10), one end of the pressing column (161) presses against the side of the metal pipe. As the metal pipe bends and moves downward, the spring rod (162) returns to its initial position when one end of the pressing column (161) is removed from the metal pipe.

4. The hydraulic press with a toggle mechanism for processing metal parts according to claim 1, characterized in that, The central mold (10) is also symmetrically provided with pipe fitting follow-up support mechanism (8) for supporting the suspended end of the metal pipe fitting on the front and rear sides; the pipe fitting follow-up support mechanism (8) includes a base (84), a support arm (83), a swing arm (82), a pin (86), a support block (81) and a follow-up torsion spring. The base (84) is slidably connected to the workbench (1), the lower end of the support arm (83) is locked to the base (84), the upper end of the support arm (83) is slidably connected to the swing arm (82), the support block (81) is fixedly set at the top of the swing arm (82), the pin (86) is connected to the bottom end of the swing arm (82), and the two ends of the pin (86) are rotatably connected to the lower mold base (12); the follower torsion spring is sleeved on the pin (86), one end of which acts on the lower mold base (12), and the other end acts on the swing arm (82), providing the swing arm (82) with a continuous torque to swing toward the center mold (10), so that the support block (81) always sticks to the bottom of the metal tube during the bending process.

5. The hydraulic press with a toggle mechanism for processing metal parts according to claim 4, characterized in that, A limiting member (85) is fixed on the base (84). The limiting member (85) is located on the worktable (1) and is used to limit the initial position of the base (84), thereby limiting the initial opening position of the swing arm (82) swinging outward. The bottom of the base (84) is rotatably provided with a one-way locking structure (14), which includes a locking block (141), a top post (142), a rotating block (143) and a reset torsion spring (144). The reset torsion spring (144) is located on both sides of the rotating block (143), and the corresponding position of the base (84) is provided with a slot that cooperates with the locking block (141). The reset torsion spring (144) normally drives the one-way locking structure (14) to rotate out and engage in the slot, thus locking the position of the swing arm (82). When the linkage arm (6) moves upward, it pushes the rotating block (143) upward through the top material mechanism, so that it overcomes the torque of the reset torsion spring and rotates to a horizontal state. The upper end disengages from the slot to release the lock. The swing arm (82) swings outward to reset under the gravity of the metal pipe and abuts against the limiting member (85).

6. The hydraulic press with a toggle mechanism for processing metal parts according to claim 1, characterized in that, The ejector mechanism includes an ejector rod (15) that penetrates vertically through the central mold (10) and a bottom crossbeam (13) set at the bottom of the workbench (1); the lower end of the ejector rod (15) is fixed on the bottom crossbeam (13), and the lower end of the linkage arm (6) extends to the bottom of the bottom crossbeam (13) and drives the bottom crossbeam (13) to move upward through the hook structure.

7. The hydraulic press with a toggle mechanism for processing metal parts according to claim 6, characterized in that, The bottom crossbeam (13) is provided with multiple sets of elastic locking components; When the moving mold base (5) moves downward, the bottom crossbeam (13) moves downward through multiple sets of elastic locking components; when the moving mold base (5) moves upward, the two ends of the bottom crossbeam (13) are pushed by the hanging structure to forcibly pull up the bottom crossbeam (13) and the ejector rod (15) to complete the mechanical demolding; the bottom crossbeam (13) is provided with ejection reset structure (17) on both sides. The ejection reset structure (17) includes an ejector rod (171) and a lifting plate (172). The lifting plate (172) is connected to the bottom crossbeam (13). The lower end of the ejector rod (171) is connected to the lifting plate (172), and its upper end presses against the vertical toggle mechanism (7). As the moving mold base (5) moves upward to the top, the ejector rod (171) opens and unlocks the vertical toggle mechanism (7), so that the follower clamp (78) moves to one side.

8. The hydraulic press with a toggle mechanism for processing metal parts according to claim 1, characterized in that, The workbench (1) is also provided with a fine-tuning stop mechanism (11) for limiting the initial position of the end of the lower mold base (12). The fine-tuning stop mechanism (11) includes a fixed bracket, a horizontal adjusting screw and a limiting top block.

9. The hydraulic press with a toggle mechanism for processing metal parts according to claim 2, characterized in that, The top of the central mold (10) is provided with a U-shaped forming cavity. The inner side of the follower clamping block (78) facing the central mold (10) is provided with an arc-shaped clamping surface that matches the U-shaped forming cavity, so as to envelop and position the metal pipe when clamping, and prevent it from going out of round.

10. The hydraulic press with a toggle mechanism for processing metal parts according to claim 3, characterized in that, The buffer spring assembly (74) includes a limiting ring (742) and an elastic rod (741). One end of the elastic rod (741) is fixedly connected to the follower clamp (78), and the other end of the elastic rod (741) is movably connected to the limiting ring (742). As the moving mold base (5) continues to descend, the limiting ring (742) restricts the push rod (73) from rotating freely, the follower roller (71) moves inward, and the elastic rod (741) ensures continuous pressure on the follower clamp (78) laterally.

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