An outer circle positioning fixture adaptive to steel pipe diameter

Abstract

The present application relates to the technical field of pipe clamping equipment, in particular to an outer circle positioning clamp self-adapting to the diameter of a steel pipe, comprising a base and a synchronous assembly, the base is provided with a plurality of main sliding blocks, the main sliding blocks can slide synchronously along the radial direction under the action of the synchronous assembly; each main sliding block is sleeved with an intermediate cylinder, the intermediate cylinder and the main sliding block can slide relative to each other; each intermediate cylinder is fixedly inserted with an elastic baffle, the elastic baffles can form a stop cooperation; the intermediate cylinder is connected with the base through a one-way assembly, the intermediate cylinder can move inward in one direction under the action of the one-way assembly; each intermediate cylinder is inserted with a clamping head, the clamping head is connected with the intermediate cylinder through a first elastic piece, and the clamping head is used for clamping the steel pipe from the outside; each clamping head is provided with an unlocking part, the unlocking part can rotate around the axis of the intermediate cylinder, and can form a stop cooperation with the elastic baffles. Thus, when clamping steel pipes with different diameters, the clamping force can be ensured to be consistent.

Description

Technical Field

[0001] This invention relates to the field of pipe clamping equipment technology, and in particular to an adaptive steel pipe diameter outer circle positioning clamp. Background Technology

[0002] In the steel pipe processing flow, precise and stable clamping is a crucial prerequisite for ensuring the processing accuracy of each stage. Since the processing involves multiple operations such as cutting, welding, and grinding, the steel pipe needs to maintain a fixed posture throughout the various processes. Therefore, the performance of the clamping mechanism directly affects the quality of the final product. Currently, the mainstream clamping methods in the industry can be divided into two main categories: external clamping and internal clamping. Among them, external clamping is particularly widely used in small and medium-sized steel pipe processing scenarios due to its convenient operation and wide adaptability.

[0003] In related technologies, the multi-pipe processing fixture for steel pipe production and processing disclosed in Chinese Patent CN210967897U is a typical application of the external cylindrical clamping method. The core working principle of this fixture is as follows: the steel pipe is placed between two symmetrically distributed clamping blocks; during the insertion of the steel pipe, its outer wall will simultaneously apply pressure to both sides, forcing the clamping blocks to drive the spring telescopic rod to move outward. As the spring telescopic rod is compressed, the elastic potential energy stored inside is converted into a clamping force on the steel pipe, thereby achieving rapid fixation of the steel pipe.

[0004] However, the aforementioned multi-pipe processing fixtures for steel pipe production and processing also present some problems in actual use: When the wall thickness and material of the steel pipe remain constant (i.e., its resistance to deformation is stable), increasing the pipe diameter will directly lead to a proportional increase in the compression of the spring extension rod. According to Hooke's Law, the spring force is linearly positively correlated with the deformation, which means that the larger the diameter of the steel pipe, the greater the clamping force. At this time, excessive clamping force can easily exceed the bearing limit of the outer surface of the steel pipe: for steel pipes made of ductile materials, it may cause local dents or scratches; for steel pipes made of brittle materials, it may cause irreversible damage such as cracks. These surface defects not only affect the appearance quality of the steel pipe, but also lead to stress concentration in subsequent processing, thereby reducing the processing dimensional accuracy and the ability to control geometric tolerances, ultimately adversely affecting the mechanical properties and service life of the product. Summary of the Invention

[0005] Therefore, it is necessary to provide an adaptive steel pipe diameter outer circle positioning fixture to address the problem of poor clamping effect in the current steel pipe processing.

[0006] The above objectives are achieved through the following technical solutions:

[0007] An adaptive steel pipe diameter outer circle positioning fixture includes a base and a synchronization component. Multiple main sliders are circumferentially arranged on the base. Under the action of the synchronization component, the main sliders can slide synchronously in the radial direction. An intermediate cylinder is sleeved on each main slider. The intermediate cylinder and the main slider can slide relative to each other in the radial direction. When the main slider slides outward, it can form a stop with the intermediate cylinder and move outward together. An elastic baffle is fixedly inserted into each intermediate cylinder. When the main slider slides inward, it can form a stop with the elastic baffle. The stop engages and drives the intermediate cylinder to move inward together; the intermediate cylinder is connected to the base through a one-way component, and under the action of the one-way component, the intermediate cylinder can move inward in one direction; each intermediate cylinder is equipped with a clamping head, and the clamping head is connected to the intermediate cylinder through a first elastic element. Under the action of the first elastic element, the clamping head and the intermediate cylinder can slide elastically relative to each other in the radial direction, and the clamping head is configured to clamp the steel pipe from the outside; each clamping head is provided with an unlocking part, and the unlocking part can form a stop engagement with the elastic baffle to disengage the elastic baffle from the main slider.

[0008] Furthermore, the unlocking part has an inclined arc surface, which can form a stop engagement with the elastic baffle. The unlocking part can rotate around the axis of the intermediate cylinder to change the corresponding position of the inclined arc surface and the elastic baffle.

[0009] Furthermore, the synchronization component includes a first arc groove and a rotating ring. Multiple first arc grooves are formed circumferentially on the base. The rotating ring is disposed on the base and is capable of rotating around its own axis. Multiple guide sliders are fixedly disposed on the rotating ring, and the guide sliders are slidably inserted into the first arc grooves. Multiple second arc grooves are formed circumferentially on the rotating ring. Each main slider is fixedly disposed with a secondary slider, and the secondary slider is slidably inserted into the second arc groove. Multiple fixing parts are fixedly disposed circumferentially on the base, and the fixing parts are connected to the guide sliders via second elastic elements.

[0010] Furthermore, the unidirectional component includes a ratchet and a ratchet bar. Each intermediate cylinder is fixedly provided with a ratchet, which extends in a direction parallel to the axis of the intermediate cylinder. The base is provided with a plurality of ratchet bars in the circumferential direction. The ratchet bars are elastically sliding in a direction perpendicular to the axis of the intermediate cylinder and are configured to form a unidirectional engagement with the ratchet.

[0011] Furthermore, each of the intermediate cylinders is threaded with an adjusting nut, and the first elastic element is connected between the adjusting nut and the clamping head. When the adjusting nut rotates, it can adjust the degree of deformation of the first elastic element.

[0012] Furthermore, each clamping head is fitted with a top cylinder and a guide post. The top cylinder is connected to the clamping head via a third elastic element. Under the action of the third elastic element, the top cylinder and the clamping head can elastically slide relative to each other in the radial direction. The top cylinder can form a stop engagement with the steel pipe. The unlocking part is fixedly disposed on the guide post. The unlocking part has an inclined arc surface, which can form a stop engagement with the elastic baffle. The guide post can rotate around its own axis and is connected to the top cylinder via a guide assembly. Under the action of the guide assembly, when the top cylinder slides radially, it can drive the guide post to rotate.

[0013] Furthermore, the guide assembly includes a first groove and a guide block. The first groove is formed on the circumferential sidewall of the top cylinder and has an arc-shaped structure. The guide block is fixedly disposed on the circumferential sidewall of the guide post and is slidably inserted into the first groove.

[0014] Furthermore, there are multiple first grooves arranged circumferentially; there are multiple guide blocks arranged circumferentially.

[0015] Furthermore, there are multiple elastic baffles arranged circumferentially; there are multiple unlocking parts arranged circumferentially.

[0016] Furthermore, the clamping surface of the clamping head is V-shaped.

[0017] The beneficial effects of this invention are:

[0018] This invention relates to an adaptive steel pipe diameter outer circle positioning clamp. By incorporating an intermediate cylinder and an unlocking part, along with a cooperating one-way component and an elastic stop plate, when clamping steel pipes of different diameters, once the first elastic element reaches a preset deformation, the unlocking part, through its stop engagement with the elastic stop plate, disengages the elastic stop plate from the main slider. Simultaneously, under the action of the one-way component, the intermediate cylinder cannot move outward, thus maintaining the deformation of the first elastic element. This ensures that the clamping force applied by the first elastic element to steel pipes of different diameters through the clamping head remains consistent. This avoids both surface defects and stress concentration caused by excessive clamping force, and unstable clamping caused by insufficient clamping force, thereby improving the clamping effect on the steel pipe and ultimately enhancing the processing quality of the steel pipe.

[0019] Furthermore, by setting the unlocking part to have an inclined arc surface that can form a stop with the elastic baffle, and by utilizing the rotatable characteristic of the unlocking part, when clamping steel pipes with different thicknesses and / or materials and / or surface finishes, the timing of the elastic baffle disengaging from the main slider can be adjusted by changing the corresponding position of the inclined arc surface and the elastic baffle. This can change the preset deformation of the first elastic element and change the clamping force of the first elastic element on the steel pipes with different thicknesses and / or materials and / or surface finishes through the clamping head, thereby improving applicability.

[0020] Furthermore, by setting an adjusting nut and utilizing its spatial position characteristics, after the first elastic element reaches a preset deformation, rotating the adjusting nut can change the degree of deformation of the first elastic element, thereby changing the clamping force of the first elastic element on the steel pipe through the clamping head, which helps to improve applicability.

[0021] Furthermore, by setting up a top cylinder and a guide post, and utilizing the motion coordination between the top cylinder and the guide post, during the clamping process of the steel pipe, the smaller the diameter of the steel pipe, the farther the top cylinder moves outward, and the larger the rotation angle of the guide post. This makes the lower position of the inclined arc surface correspond to the elastic baffle, thus delaying the timing of the elastic baffle and the main slider disengaging. Consequently, the preset deformation of the first elastic element is larger, and the clamping force of the first elastic element on the steel pipe through the clamping head is greater, thereby improving the clamping stability of steel pipes with smaller diameters. Attached Figure Description

[0022] Figure 1 A three-dimensional structural diagram of the adaptive steel pipe diameter outer circle positioning clamp provided in this embodiment of the invention when clamping the steel pipe. Figure 1 ;

[0023] Figure 2 This is a front view of the adaptive steel pipe diameter outer circle positioning fixture provided in an embodiment of the present invention when clamping a steel pipe.

[0024] Figure 3 for Figure 2 Sectional view along the AA direction;

[0025] Figure 4 This is a top view of the adaptive steel pipe diameter outer circle positioning fixture provided in an embodiment of the present invention when clamping a steel pipe.

[0026] Figure 5 for Figure 4 Sectional view along the BB direction;

[0027] Figure 6 for Figure 5 A magnified schematic diagram of the structure at point X in the middle;

[0028] Figure 7This is an exploded view of the parts of the adaptive steel pipe diameter outer circle positioning fixture provided in an embodiment of the present invention when clamping a steel pipe.

[0029] Figure 8 for Figure 7 A magnified schematic diagram of the structure at point Y in the middle;

[0030] Figure 9 A three-dimensional structural diagram of the adaptive steel pipe diameter outer circle positioning clamp provided in this embodiment of the invention when clamping the steel pipe. Figure 2 ;

[0031] Figure 10 A three-dimensional structural diagram of the adaptive steel pipe diameter outer circle positioning clamp provided in this embodiment of the invention when clamping the steel pipe. Figure 3 ;

[0032] Figure 11 for Figure 10 A magnified schematic diagram of the structure at point Z in the middle;

[0033] Figure 12 This is an exploded view of the top cylinder and guide post of the adaptive steel pipe diameter outer circle positioning fixture provided in an embodiment of the present invention.

[0034] in:

[0035] 1. Base; 101. Mounting groove; 102. Slide rail; 201. First arc groove; 202. Rotating ring; 2021. Guide slider; 2022. Second arc groove; 2023. Mounting seat; 2024. Stop block; 203. Secondary slider; 2031. Guide tube; 204. Fixing part; 3. Main slider; 301. Step surface; 4. Intermediate cylinder; 401. Elastic baffle; 5. One-way assembly; 501. Ratchet; 502. Ratchet bar; 6. Clamping head; 7. First helical spring; 8. Unlocking part; 801. Inclined arc surface; 9. Adjusting nut; 10. Top cylinder; 11. Guide post; 12. Second helical spring; 13. Guide assembly; 1301. First slide groove; 1302. Guide block; 14. Third helical spring; 15. Fourth helical spring; 16. Crank handle; 17. Steel pipe. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0037] The following reference Figures 1 to 12 The adaptive steel pipe diameter outer circle positioning fixture provided in the embodiments of the present invention is particularly suitable for clamping steel pipe 17, and of course, it is also suitable for clamping pipes of other materials.

[0038] Specifically, the adaptive steel pipe diameter outer circle positioning fixture is configured to include a base 1, which is an annular structure and remains stationary; multiple mounting slots 101 are formed through the circumferential sidewall of the base 1, which are evenly arranged circumferentially and extend radially along the base 1; a main slider 3 is inserted into each mounting slot 101, and a clamping head 6 is connected to each main slider 3 through a first elastic element. The first elastic element can be a first helical spring 7, which is sleeved on the clamping head 6 during installation. Thus, the clamping head 6 guides the first helical spring 7, ensuring that the release direction of the elastic force of the first helical spring 7 is always radial, avoiding the generation of ineffective component force. Under the action of the first helical spring 7, the clamping head 6 can elastically slide along the radial direction of the base 1.

[0039] During use, the steel pipe 17 is placed inside the base 1, and its outer peripheral wall simultaneously applies pressure to the clamping head 6, forcing the clamping head 6 to move outward while compressing the first helical spring 7. As the first helical spring 7 is compressed, the elastic force it generates is converted into a clamping force applied to the steel pipe 17 through the clamping head 6, thereby achieving stable clamping of the steel pipe 17.

[0040] However, when the wall thickness and material of the steel pipe 17 remain constant (i.e., its resistance to deformation is stable), increasing the diameter of the steel pipe 17 will directly lead to a proportional increase in the compression of the first helical spring 7. According to Hooke's Law, the linear positive correlation between the elastic force and deformation of the first helical spring 7 means that a larger diameter steel pipe 17 will inevitably bear a larger clamping force. This mechanical relationship has significant hidden dangers: for the ductile steel pipe 17, excessive clamping force can easily cause local plastic deformation, forming dents or scratches; for the brittle steel pipe 17, it may exceed the yield limit of the material, resulting in irreversible damage such as cracks.

[0041] The impact of these surface defects extends beyond appearance quality, creating a chain reaction in subsequent processing stages. For example, in cutting, recessed areas can cause uneven tool stress, leading to vibration errors; in welding, stress concentration at scratches can result in uneven weld penetration; and during precision grinding, cracks can cause fluctuations in material removal, ultimately causing dimensional accuracy and form tolerances to deviate from design requirements. In long-term use, steel pipes with surface defects will become stress concentration sources under load, accelerating fatigue failure and severely impacting the product's mechanical properties and service life.

[0042] Based on this, in the adaptive steel pipe diameter outer circle positioning fixture provided in the embodiment of the present invention, the main slider 3 is configured to slide along the radial direction of the base 1; the adaptive steel pipe diameter outer circle positioning fixture also includes a synchronization component, under the action of the synchronization component, multiple main sliders 3 can slide synchronously along the radial direction, thereby realizing the rapid clamping and disassembly of the steel pipe 17. The main slider 3 is a strip structure that extends radially along the base 1 and has a large end and a small end. When the main slider 3 is installed, the large end is on the outside. An intermediate cylinder 4 is sleeved on the small end of each main slider 3. The axis of the intermediate cylinder 4 extends radially along the base 1. The intermediate cylinder 4 and the main slider 3 can slide relative to each other in the radial direction of the base 1. The inner end of the intermediate cylinder 4 is open. A clamping head 6 is inserted into the inner end of each intermediate cylinder 4. The first helical spring 7 is sleeved on the clamping head 6 during installation and is connected between the inner end of the intermediate cylinder 4 and the clamping head 6. Under the action of the first helical spring 7, the clamping head 6 can slide elastically relative to the intermediate cylinder 4 in the radial direction. The small end of the main slider 3 has a stepped structure, and the stepped surface 301 can form a stop fit with the inner end face of the outer end of the intermediate cylinder 4, thereby driving the intermediate cylinder 4 and the clamping head 6 to move outward together to make way for the steel pipe 17 to be placed inside the base 1.

[0043] Each intermediate cylinder 4 is fixedly fitted with an elastic baffle 401. The elastic baffle 401 is a strip-shaped structure, parallel to the axis of the intermediate cylinder 4, and Z-shaped. One bent section faces the inner circumferential wall of the intermediate cylinder 4 and is fixed thereon, while the other bent section faces the small end of the main slider 3 and abuts against the side wall of the small end of the main slider 3. The small end of the main slider 3 can form a stop engagement with the outer end of the elastic baffle 401, thereby driving the intermediate cylinder 4 and the clamping head 6 to move inward together, thus clamping the steel pipe 17. Each clamping head 6 has an unlocking part 8 on its outer end face. The unlocking part 8 can form a stop engagement with the inner end of the elastic baffle 401, thereby driving the outer end of the elastic baffle 401 to rotate around its own inner end, thus moving the outer end of the elastic baffle 401 away from the main slider 3, thereby disengaging the elastic baffle 401 from the main slider 3. Optionally, the unlocking part 8 can be configured as a triangular structure with its tip pointing towards the small end of the main slider 3.

[0044] As an example, the number of mounting slot 101, main slider 3, intermediate cylinder 4, first helical spring 7 and clamping head 6 can all be set to three to achieve three-point positioning and clamping of steel pipe 17.

[0045] Taking a case where there are three clamping heads 6 as an example. Initially, the small end of the main slider 3 is located outside the outer end of the elastic baffle 401.

[0046] During operation, the three main sliders 3 are first moved outward synchronously by the synchronization component. Taking one of the main sliders 3 as an example, when it reaches a stop position where the step surface 301 and the inner end face of the outer end of the intermediate cylinder 4 form a stop, the intermediate cylinder 4, the first helical spring 7, and the clamping head 6 move outward synchronously as the main slider 3 continues to move outward, thus making way for the placement of the steel pipe 17. Then, the steel pipe 17 is placed inside the base 1 by hand or with a robotic arm, ensuring it is as coaxial as possible with the base 1. Finally, the three main sliders 3 are moved inward synchronously by the synchronization component. During the movement of the main slider 3, taking one of the main sliders 3 as an example, when the main slider 3 moves to the point where its small end and the outer end of the elastic baffle 401 form a stop engagement, as the main slider 3 continues to move inward, it synchronously drives the intermediate cylinder 4, the first helical spring 7, and the clamping head 6 to move inward together. When the clamping head 6 contacts the outer peripheral wall of the steel pipe 17, the position of the clamping head 6 remains unchanged, and the intermediate cylinder 4 continues to move inward under the drive of the main slider 3, synchronously compressing the first helical spring 7. As the first helical spring 7 is compressed, the elastic force it generates is converted into a clamping force applied to the steel pipe 17 through the clamping head 6, thereby achieving stable clamping of the steel pipe 17.

[0047] When clamping steel pipes 17 with different diameters, the clamping head 6 contacts the outer peripheral wall of the steel pipe 17 earlier when clamping a larger diameter steel pipe 17, and contacts the outer peripheral wall of the steel pipe 17 later when clamping a smaller diameter steel pipe 17, but the other processes are exactly the same. As the first helical spring 7 is compressed, when the first helical spring 7 reaches the preset deformation, the unlocking part 8 and the inner end of the elastic baffle 401 form a stop engagement, and then drive the outer end of the elastic baffle 401 to rotate around its own inner end, so that the outer end of the elastic baffle 401 moves away from the side wall of the main slider 3, thereby disengaging the elastic baffle 401 from the main slider 3. At this time, the intermediate cylinder 4 is in a free state, while the first helical spring 7 is in a compressed state. Under the elastic force of the first helical spring 7, the intermediate cylinder 4 has a tendency to move outward, but under the action of the one-way component 5, the intermediate cylinder 4 cannot move outward. The ability to maintain the deformation of the first helical spring 7 ensures that the clamping force applied by the first helical spring 7 to steel pipes 17 of different diameters through the clamping head 6 remains consistent. For large-diameter steel pipes 17, the bearing area of ​​its outer peripheral wall is larger, and the pressure generated by the same clamping force is smaller, which can avoid exceeding the yield limit of the material and causing surface defects such as dents and scratches. For small-diameter steel pipes 17, although the bearing area is smaller, the clamping force will not decrease due to the reduction in diameter, which can ensure sufficient friction to offset external force interference during processing and prevent the steel pipe 17 from slipping or rotating, thereby solving the problem of unstable clamping.

[0048] In the processing flow, a stable clamping state provides a fundamental guarantee for the accuracy of each process. When the steel pipe 17 is clamped evenly and appropriately, the stress stability during operations such as cutting, welding, and grinding is significantly improved: during cutting, the relative positional deviation between the tool and the steel pipe 17 is reduced, avoiding cut tilting caused by vibration; during welding, thermal deformation is uniform, reducing stress concentration in the weld caused by uneven clamping force; during grinding, the surface roughness consistency is improved, eliminating the need for repeated adjustments to processing parameters due to excessive local stress. This overall stability ultimately translates into improved processing quality, ensuring the dimensional accuracy and form and position tolerances of the steel pipe 17, and reducing the scrap rate caused by clamping problems, fundamentally optimizing production efficiency and product reliability.

[0049] In a further embodiment, the synchronization component may be configured to include a first arc groove 201 and a rotating ring 202. Multiple first arc grooves 201 are formed on the front end face of the base 1, the number of which is equal to the number of clamping heads 6, and they are evenly arranged circumferentially, alternating with the mounting groove 101 circumferentially. The first arc grooves 201 are arc-shaped and coaxially arranged with the base 1. The rotating ring 202 is coaxially arranged on the front sidewall of the base 1 and can rotate around its own axis. Multiple guide sliders 2021 are vertically fixed on the rear end face of the rotating ring 202, the number of which is equal to the number of clamping heads 6, and they are evenly arranged circumferentially. The guide sliders 2021 are slidably inserted into the first arc grooves 201 during installation. Multiple second arc grooves 2022 are formed through the ring surface of the rotating ring 202, the number of which is equal to the number of clamping heads 6, and they are evenly arranged circumferentially, alternating with the guide sliders. The second arc groove 2022 is arranged alternately along the circumference, with one end inside and the other end outside, and the two ends are staggered along the circumference. The mounting groove 101 penetrates the front end face of the base 1. A slide rail 102 is fixedly inserted in each mounting groove 101. The slide rail 102 extends radially along the base 1. The main slider 3 slides onto the slide rail 102 during installation. A secondary slider 203 is fixed to the front end face of each main slider 3 by screws. A guide tube 2031 is integrally formed on the front end face of each secondary slider 203. The guide tube 2031 passes forward through the mounting groove 101 and slides into the second arc groove 2022 during installation. A bolt is threaded into each guide tube 2031. The head of the bolt is located on the front side of the rotating ring 202 and forms a stop with the rotating ring 202. Thus, the rotating ring 202 can be restricted on the base 1 by the slide rail 102, the main slider 3, the secondary slider 203 and the bolt, and axial positioning can be achieved.

[0050] Multiple fixing parts 204 are fixedly provided on the rear end face of the base 1. The number of fixing parts 204 is equal to the number of clamping heads 6, and they are evenly arranged circumferentially and alternately arranged with the first arc groove 201 circumferentially. The fixing parts 204 are connected to the guide slider 2021 through a second elastic element. The second elastic element can be a second helical spring 12. The fixing parts 204 can be integrally formed with the base 1, or they can be a bolt structure and threaded into the base 1. Taking the fixing parts 204 as a bolt structure as an example, a bolt is threaded into each guide slider 2021. The head of the bolt is located on the rear side of the base 1. When the second helical spring 12 is installed, one end is sleeved on the shank of the bolt, and the other end is sleeved on the shank of the fixing part 204.

[0051] Initially, the guide slider 2021 is located at one end of the first arc groove 201; the guide tube 2031 is located at the inner end of the second arc groove 2022; the first arc groove 201 and the second arc groove 2022 are offset in the circumferential direction.

[0052] During use, one of the guide sliders 2021 is manually slid along the first arc groove 201 to the other end, and the second helical spring 12 connected to the guide slider 2021 is simultaneously stretched and stored. During the movement of the guide slider 2021, it simultaneously drives the rotating ring 202 to rotate in the positive direction around its own axis; when the rotating ring 202 rotates, on the one hand, through the other guide sliders 2021 sliding along the first arc groove 201 to the other end, the other second helical springs 12 are simultaneously stretched; on the other hand, through the second arc groove 2022, all the conduits 2031 are driven to move outward synchronously, and the conduits 2031 drive the main slider 3 to move outward synchronously through the auxiliary slider 203.

[0053] After the steel pipe 17 is placed inside the base 1, the guide slider 2021 is released. Under the pull of the second helical spring 12, all the guide sliders 2021 are synchronously reset. The guide sliders 2021 simultaneously drive the rotating ring 202 to rotate in the opposite direction around its own axis. When the rotating ring 202 rotates, it drives all the conduits 2031 to move inward synchronously through the second arc groove 2022. The conduits 2031 drive the main slider 3 to move inward synchronously through the auxiliary slider 203.

[0054] In other embodiments, the one-way component 5 is configured to include a ratchet 501 and a ratchet bar 502. A ratchet 501 is fixedly provided on the outer peripheral wall of each intermediate cylinder 4, and the ratchet 501 extends in a direction parallel to the axis of the intermediate cylinder 4. A ratchet bar 502 is inserted into each mounting groove 101. The ratchet bar 502 is located at the inner end of the mounting groove 101 and extends in a direction parallel to the axis of the base 1. The ratchet bar 502 also extends rearward through the base 1, and a stop is integrally formed at the rear end of the ratchet bar 502. A fourth helical spring 15 is sleeved on the ratchet bar 502. The fourth helical spring 15 abuts between the stop and the rear end face of the base 1. Under the action of the fourth helical spring 15, the ratchet bar 502 can elastically slide in a direction perpendicular to the axis of the intermediate cylinder 4 and can form a one-way engagement with the ratchet 501. Furthermore, the cross-sectional shape of the ratchet 502 can be set to non-circular, such as ellipse, triangle, rectangle, irregular shape (clover, polygon (more than four sides)), etc., thereby restricting the rotational freedom of the ratchet 502 and avoiding affecting the unidirectional engagement between it and the ratchet 501.

[0055] During use, when the intermediate cylinder 4 moves outward, the ratchet 502 can be manually pulled to disengage it from the ratchet 501, thus avoiding affecting the movement of the intermediate cylinder 4. At this time, the fourth helical spring 15 is in a compressed state. When the intermediate cylinder 4 moves inward, the ratchet 502 is released, and under the elastic force of the fourth helical spring 15, the ratchet 502 returns to its original position, thus forming a one-way engagement with the ratchet 501 to restrict the outward movement of the intermediate cylinder 4.

[0056] In a further embodiment, to achieve automatic unlocking of the one-way component 5, multiple mounting seats 2023 are fixedly mounted on the front end face of the rotating ring 202. The number of mounting seats 2023 is equal to the number of the second arc groove 2022, and they are evenly arranged circumferentially and adjacent to the second arc groove 2022. A stop block 2024 is hinged to each mounting seat 2023. The front end face of the ratchet 502 is an inclined surface, which can form a guiding engagement with the stop block 2024. Thus, during the forward rotation of the rotating ring 202, the stop block 2024 and the mounting seat 2023 form a stop engagement, ensuring that the ratchet 502 can be driven to move backward, so that the ratchet 502 and the ratchet 501 disengage from the one-way engagement, avoiding affecting the outward movement of the intermediate cylinder 4. During the reverse rotation of the rotating ring 202, the stop block 2024 can rotate freely, preventing the ratchet 502 from moving backward, and ensuring the stability of the one-way engagement between the ratchet 502 and the ratchet 501.

[0057] In other embodiments, the physical properties of the steel pipe 17 are the core factor determining the required clamping force, and there is a dynamic adaptation relationship between the two. The essence of this adaptation is that the clamping force must simultaneously meet two constraints: first, to provide sufficient friction to resist external forces during processing (such as cutting forces, welding stresses, etc.) and ensure clamping stability; second, to not exceed the deformation resistance of the steel pipe 17 material to avoid surface damage or structural destruction.

[0058] When the physical properties of the steel pipe 17 change, its clamping force requirement will adjust systematically: For steel pipe 17 with increased hardness or thickness, its yield strength and resistance to deformation increase simultaneously. In this case, a larger clamping force will not cause defects such as surface depressions or cracks. Instead, it can increase the friction by increasing the normal pressure on the contact surface, effectively offsetting the torque and axial force during processing, preventing the steel pipe 17 from slipping or deflecting, thus ensuring clamping stability. When the surface finish of the steel pipe 17 increases, the coefficient of friction of the contact surface will decrease significantly. Under the same clamping force, the decrease in friction may cause relative displacement of the steel pipe 17 during processing. Therefore, it is necessary to increase the clamping force to compensate for the loss of the coefficient of friction in order to maintain sufficient constraint effect.

[0059] Conversely, when the physical properties of the steel pipe 17 change in the opposite direction, the clamping force needs to be reduced accordingly. For steel pipes 17 that are softer or thinner, their resistance to deformation is weaker. If the clamping force is too large, it is easy to cause local plastic deformation or structural damage, and even cause the cross-section of the steel pipe 17 to become out of round, affecting the datum accuracy of subsequent processing. Therefore, reducing the clamping force is a necessary measure to avoid over-clamping. When the surface roughness of the steel pipe 17 increases, the mechanical interlocking effect of the contact surface is enhanced, and the coefficient of friction increases accordingly. At this time, a smaller clamping force can generate sufficient frictional force to constrain the steel pipe 17. In addition, reducing the clamping force can also reduce the long-term deformation load of the first helical spring 7, delay the fatigue aging process, and extend the service life of the fixture.

[0060] Based on this, in the adaptive steel pipe diameter outer circle positioning fixture provided in this embodiment of the invention, one of the side wall surfaces of the unlocking part 8 can be configured as an inclined arc surface 801, and the inclined arc surface 801 can form a stop engagement with the elastic baffle 401. This allows the elastic baffle 401 to disengage from the main slider 3 after the first helical spring 7 reaches a preset deformation, thereby maintaining the deformation of the first helical spring 7. The unlocking part 8 can rotate around the axis of the intermediate cylinder 4 to change the corresponding positions of the inclined arc surface 801 and the elastic baffle 401. Thus, when the steel pipe 17 hardens and / or its thickness increases and / or its surface becomes smoother, rotating the unlocking part 8 causes the lower point on the inclined arc surface 801 to correspond to the position of the elastic baffle 401, thereby delaying the disengagement of the elastic baffle 401 from the main slider 3. This increases the preset deformation of the first helical spring 7, increasing the clamping force of the first helical spring 7 on the steel pipe 17 through the clamping head 6, and improving clamping stability.

[0061] Conversely, when the steel pipe 17 softens and / or its thickness decreases and / or its surface becomes rougher, rotating the unlocking part 8 causes the higher point on the inclined arc surface 801 to correspond to the position of the elastic baffle 401. This allows the elastic baffle 401 to disengage from the main slider 3 earlier, thereby reducing the preset deformation of the first helical spring 7. This reduces the clamping force of the first helical spring 7 on the steel pipe 17 through the clamping head 6, ensuring clamping stability while avoiding over-clamping.

[0062] In other embodiments, in order to make the clamping force applied by the clamping head 6 to the steel pipe 17 change accordingly based on the physical characteristics of the steel pipe 17, it can also be set that an adjusting nut 9 is threaded onto the inner end of each intermediate cylinder 4, and the first helical spring 7 is connected between the adjusting nut 9 and the clamping head 6.

[0063] During use, when the steel pipe 17 hardens and / or its thickness increases and / or its surface becomes smoother, rotating the adjusting nut 9 causes it to move inward simultaneously, compressing the first helical spring 7. This increases the clamping force of the first helical spring 7 on the steel pipe 17 through the clamping head 6, improving clamping stability. Conversely, when the steel pipe 17 softens and / or its thickness decreases and / or its surface becomes rougher, rotating the adjusting nut 9 causes it to move both outward and inward simultaneously, releasing the first helical spring 7. This reduces the clamping force of the first helical spring 7 on the steel pipe 17 through the clamping head 6, ensuring clamping stability while avoiding over-clamping.

[0064] In other embodiments, when clamping a small-diameter steel pipe 17, its geometric characteristics directly affect the mechanical equilibrium of the clamping system. From a mechanical perspective, the cutting forces, torques, and other external forces experienced by the steel pipe 17 during processing must be offset by the frictional torque generated by the clamping mechanism. The magnitude of the frictional torque is closely related to the length of the resistance arm, which here represents the radius of the steel pipe 17—that is, the distance from the central axis of the steel pipe 17 to the clamping point.

[0065] For the small-diameter steel pipe 17, its smaller radius results in a correspondingly shorter resistance arm. According to the torque balance formula (torque = force × lever arm), under the same external force, the shorter the resistance arm, the smaller the frictional torque required to keep the steel pipe 17 stationary. However, this characteristic also means that a relatively small external force can disrupt the original torque balance: when instantaneous impact forces or unstable loads occur during processing, due to the shorter resistance arm, the disturbance torque generated by the external force is more likely to exceed the frictional torque provided by the clamping mechanism, thus causing the steel pipe 17 to rotate relative to the ground.

[0066] This rotational tendency directly affects clamping stability: on the one hand, the slight rotation of the steel pipe 17 disrupts the consistency of the machining datum, leading to deviations in positional accuracy during cutting, welding, and other processes; on the other hand, the relative sliding between the clamping point and the surface of the steel pipe 17 during rotation may generate additional frictional damage, exacerbating surface defects. Furthermore, the small-diameter steel pipe 17 has relatively weak rigidity; once rotation occurs, uneven stress may cause bending deformation, further reducing machining quality.

[0067] Based on this, in the adaptive steel pipe diameter outer circle positioning fixture provided in this embodiment of the invention, a top cylinder 10 and a guide post 11 are inserted into each clamping head 6. The top cylinder 10 and the intermediate cylinder 4 are coaxially arranged, and the inner end of the top cylinder 10 extends out of the clamping head 6 to facilitate a stop fit with the outer peripheral wall of the steel pipe 17. The guide post 11 and the intermediate cylinder 4 are coaxially arranged and located outside the top cylinder 10, with its front end inserted into the top cylinder 10. The top cylinder 10 is connected to the clamping head 6 through a third elastic element, which can be a third helical spring 14. A stop is integrally formed at the front end of the top cylinder 10. The third helical spring 14 is sleeved on the top cylinder 10 during installation and is located between the stop and the clamping head 6. Under the action of the third helical spring 14, the top cylinder 10... The 0 can slide elastically in the radial direction relative to the clamping head 6; the unlocking part 8 is fixedly set on the outer end face of the guide post 11, one side wall of the unlocking part 8 is an inclined arc surface 801, and the inclined arc surface 801 can form a stop engagement with the elastic baffle 401, so that after the first helical spring 7 reaches the preset deformation, the elastic baffle 401 and the main slider 3 can be disengaged, thereby maintaining the deformation of the first helical spring 7; the guide post 11 can rotate around its own axis, and is connected to the top cylinder 10 through the guide assembly 13. Under the action of the guide assembly 13, when the top cylinder 10 slides in the radial direction, it can drive the guide post 11 to rotate, and the guide post 11 synchronously drives the unlocking part 8 to rotate, thereby changing the corresponding position of the inclined arc surface 801 and the elastic baffle 401.

[0068] During use, when clamping the steel pipe 17, the smaller the diameter of the steel pipe 17, the farther the top cylinder 10 moves outward, and the greater the rotation angle of the guide column 11. This causes the lower position of the inclined arc surface 801 to correspond with the elastic baffle 401, which in turn delays the timing of the elastic baffle 401 disengaging from the main slider 3. Consequently, the preset deformation of the first elastic element is greater, and the clamping force of the first elastic element on the steel pipe 17 through the clamping head 6 is greater, thereby improving the clamping stability of the steel pipe 17 with a smaller diameter.

[0069] Furthermore, the guide assembly 13 is configured to include a first groove 1301 and a guide block 1302. The first groove 1301 is formed on the circumferential side wall of the top cylinder 10 and has an arc-shaped structure. The guide block 1302 is fixedly set on the circumferential side wall of the guide post 11 and is slidably inserted into the first groove 1301. Thus, when the steel pipe 17 pushes the guide block 1302 outward, the guide post 11 is synchronously rotated through the cooperation between the guide block 1302 and the first groove 1301. This causes the lower position of the inclined arc surface 801 to correspond to the elastic baffle 401, thereby delaying the timing of the elastic baffle 401 disengaging from the main slider 3. Consequently, the preset deformation of the first elastic element is larger, and the clamping force of the first elastic element on the steel pipe 17 through the clamping head 6 is greater, thereby improving the clamping stability of steel pipes 17 with smaller diameters.

[0070] More specifically, in order to avoid affecting the rotation accuracy of the unlocking part 8 due to the rotation of the top cylinder 10, a second sliding groove is provided on the side wall where the clamping head 6 and the top cylinder 10 are connected. The second sliding groove extends in a direction parallel to the axis of the top cylinder 10. A guide block is fixedly provided on the outer peripheral wall of the top cylinder 10. The guide block is slidably inserted into the second sliding groove, thereby restricting the rotational freedom of the top cylinder 10.

[0071] In a further embodiment, to improve the clamping reliability of the fixture, multiple first sliding grooves 1301 are arranged circumferentially; multiple guide blocks 1302 are also arranged circumferentially. This optimizes the force transmission path and distribution, thereby improving the system's stability and anti-interference capability.

[0072] Specifically, when multiple sets of first grooves 1301 and guide blocks 1302 are evenly arranged in the circumferential direction, the torque is distributed to multiple contact points, and the load borne by each guide block 1302 is significantly reduced, which can effectively delay fatigue damage of parts and extend service life.

[0073] Meanwhile, multiple sets of circumferentially distributed mating structures can form complementary geometric constraints. A single mating pair may experience trajectory deviations due to installation errors or machining deviations; for example, a straightness error in the first groove 1301 can cause additional radial displacement of the guide block 1302. When two or more sets of circumferentially symmetrically distributed structures are used, this unidirectional deviation is offset by the symmetrical constraint relationship, making the rotation of the guide post 11 smoother and the mating position of the inclined arc surface 801 and the elastic baffle 401 more precise, thereby ensuring the consistency of the unlocking timing.

[0074] As an example, there may be two first slide grooves 1301, which are evenly arranged in the circumferential direction; correspondingly, there may be two guide blocks 1302, which are evenly arranged in the circumferential direction and are slidably inserted into the two first slide grooves 1301 respectively.

[0075] In other embodiments, to improve the clamping reliability of the fixture, multiple elastic baffles 401 are provided, arranged circumferentially; multiple unlocking parts 8 are also provided circumferentially. In this way, the uniformity of force transmission and the consistency of action response can be improved through the coordinated action of multiple contacts, thereby enhancing the clamping reliability of the fixture.

[0076] Specifically, when multiple elastic baffles 401 are evenly distributed along the circumference, the driving force of the main slider 3 is distributed to multiple contact points, and the load borne by each elastic baffle 401 is significantly reduced, which can effectively avoid structural failure caused by local overload. At the same time, it ensures that the axis of the intermediate cylinder 4 is always aligned with the radial direction of the base 1 during radial movement, providing a structural basis for the stable output of clamping force.

[0077] Simultaneously, when multiple unlocking parts 8 act synchronously along the circumference, even if there is a slight deviation at individual contact points, the coordinated action of the remaining contact points can create a compensating effect, ensuring that all elastic baffles 401 disengage from the main slider 3 at the same time. This synchronicity avoids the problem of uneven local force during clamping, ensuring that the force exerted by each clamping head 6 on the steel pipe 17 remains balanced, effectively preventing the steel pipe 17 from shifting or deforming due to unilateral force.

[0078] As an example, the number of elastic baffles 401 can be set to two, and they are evenly arranged in the circumferential direction; correspondingly, the number of unlocking parts 8 can be set to two, and they are evenly arranged in the circumferential direction.

[0079] In other embodiments, to improve the stability when clamping the steel pipe 17, the clamping surface of the clamping head 6 is configured to be V-shaped. Thus, the geometric characteristics of the V-shaped structure can achieve multiple stabilizing effects, significantly improving the clamping performance.

[0080] Specifically, the V-shaped clamping surface forms a line contact with the outer circumference of the steel pipe 17 rather than a point contact. This contact form expands the effective contact area, allowing the clamping force to be distributed more evenly on the outer circumferential wall of the steel pipe 17. For the cylindrical steel pipe 17, the two inclined surfaces of the V-shape can adapt to the curvature of the steel pipe 17. Regardless of the change in the diameter of the steel pipe 17, the contact line can remain parallel to the axis of the steel pipe 17, avoiding local stress concentration caused by single-point force and reducing the risk of plastic deformation on the surface of the steel pipe 17 due to uneven force.

[0081] In some other embodiments, to improve the convenience of rotating the guide slider 2021, a crank 16 is provided on a bolt on one of the guide sliders 2021, so that the guide slider 2021 can be driven to slide along the first arc groove 201 by the crank 16.

[0082] In other embodiments, the synchronization component may also be configured to include multiple drive cylinders, the number of drive cylinders being equal to the number of clamping heads 6, and evenly arranged circumferentially and corresponding to the clamping heads 6. The output shaft of the drive cylinder is fixedly mounted on the main slider 3 during installation, so that all the main sliders 3 can be synchronously driven to slide in the radial direction.

[0083] Understandably, the drive cylinder can be any of the following: hydraulic cylinder, pneumatic cylinder, or electric cylinder.

[0084] In other embodiments, the synchronization component may also be configured to have the same structure as the moving mechanism that drives the jaws in a three-jaw chuck.

[0085] The above-described embodiments are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A self-adaptive steel pipe diameter outer circle positioning fixture, characterized in that, The adaptive steel pipe diameter outer circle positioning fixture includes a base and a synchronization component. Multiple main sliders are circumferentially arranged on the base. Under the action of the synchronization component, the main sliders can slide synchronously in the radial direction. An intermediate cylinder is sleeved on each main slider. The intermediate cylinder and the main slider can slide relative to each other in the radial direction. When the main slider slides outward, it can form a stop with the intermediate cylinder and move outward together. An elastic baffle is fixedly inserted into each intermediate cylinder. The elastic baffle has a strip-shaped structure and is parallel to the axis of the intermediate cylinder. The elastic baffle is Z-shaped, with one bent section facing the inner circumferential wall of the intermediate cylinder and fixed to the inner circumference of the intermediate cylinder. On the wall, another bent section faces the small end of the main slider and abuts against the side wall of the small end of the main slider. When the main slider slides inward, the small end of the main slider can form a stop engagement with the outer end of the elastic baffle and drive the intermediate cylinder to move inward together. The intermediate cylinder is connected to the base through a one-way component. Under the action of the one-way component, the intermediate cylinder can move inward in one direction. Each intermediate cylinder is equipped with a clamping head. The clamping head is connected to the intermediate cylinder through a first elastic element. Under the action of the first elastic element, the clamping head and the intermediate cylinder can slide elastically relative to each other in the radial direction. The clamping head is configured to clamp the steel pipe from the outside. Each clamping head is provided with The device includes an unlocking part that can engage with the elastic baffle to disengage the elastic baffle from the main slider. Each clamping head contains a top cylinder and a guide post. The top cylinder is connected to the clamping head via a third elastic element. Under the action of the third elastic element, the top cylinder and the clamping head can elastically slide relative to each other in the radial direction. The top cylinder can also engage with the steel pipe to form a stop. The unlocking part is fixedly mounted on the guide post and has an inclined arc surface that can engage with the elastic baffle to form a stop. The guide post can rotate around its own axis and is connected to the top cylinder via a guide assembly. Under the action of the guide assembly, the top cylinder can... The first elastic element can rotate to drive the guide post. When the first elastic element reaches a preset deformation, the unlocking part and the inner end of the elastic baffle form a stop engagement, and then drive the outer end of the elastic baffle to rotate around its own inner end, so that the outer end of the elastic baffle moves away from the side wall of the main slider, thereby disengaging the elastic baffle from the main slider. In this state, under the action of the one-way component, the intermediate cylinder cannot move outward, thus maintaining the deformation of the first elastic element. The guide component includes a first slide groove and a guide block. The first slide groove is opened on the circumferential side wall of the top cylinder and has an arc-shaped structure. The guide block is fixedly disposed on the circumferential side wall of the guide post and is slidably inserted into the first slide groove.

2. The adaptive steel pipe diameter outer circle positioning fixture according to claim 1, characterized in that, The synchronization component includes a first arc groove and a rotating ring. Multiple first arc grooves are formed circumferentially on the base. The rotating ring is mounted on the base and can rotate around its own axis. Multiple guide sliders are fixedly mounted on the rotating ring, and the guide sliders are slidably inserted into the first arc grooves. Multiple second arc grooves are formed circumferentially on the rotating ring. Each main slider is fixedly mounted with a secondary slider, and the secondary slider is slidably inserted into the second arc groove. Multiple fixing parts are fixedly mounted circumferentially on the base, and the fixing parts are connected to the guide sliders via second elastic elements.

3. The adaptive steel pipe diameter outer circle positioning fixture according to claim 1, characterized in that, The unidirectional component includes a ratchet and a ratchet bar. Each intermediate cylinder is fixedly provided with a ratchet, which extends in a direction parallel to the axis of the intermediate cylinder. The base is provided with a plurality of ratchet bars in a circumferential direction. The ratchet bars are elastically sliding in a direction perpendicular to the axis of the intermediate cylinder and are configured to form a unidirectional engagement with the ratchet.

4. The adaptive steel pipe diameter outer circle positioning fixture according to claim 1, characterized in that, Each of the intermediate cylinders is threaded with an adjusting nut, and the first elastic element is connected between the adjusting nut and the clamping head. When the adjusting nut is rotated, it can adjust the degree of deformation of the first elastic element.

5. The adaptive steel pipe diameter outer circle positioning fixture according to claim 1, characterized in that, There are multiple first grooves arranged circumferentially; there are multiple guide blocks arranged circumferentially.

6. The adaptive steel pipe diameter outer circle positioning fixture according to claim 1, characterized in that, There are multiple elastic baffles arranged circumferentially; there are multiple unlocking parts arranged circumferentially.

7. The adaptive steel pipe diameter outer circle positioning fixture according to claim 1, characterized in that, The clamping surface of the clamping head is V-shaped.

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