An expansion dowel

Abstract

The utility model provides a kind of expansion type positioning pin, belong to workpiece assembly technical field, including pin body, the one end of pin body is provided with positioning boss, the other end of pin body is rotatably equipped with the shaft sleeve that can axially move, and positioning boss and pin body between, and shaft sleeve and pin body between all form step structure;The inside of pin body is opened with the installation groove and expansion groove that are connected along axial direction, the position of installation groove corresponds with positioning boss, and the diameter of installation groove is greater than the diameter of expansion groove;The inside of installation groove movably is provided with the expansion column that can be with expansion groove interference fit, and the end of expansion column close to expansion groove is connected with coaxial screw rod;The one end of shaft sleeve away from pin body is provided with plugging platform, and plugging platform is screw-connected with screw rod.The utility model makes pin body expand by shaft sleeve rotation drive expansion column, can realize positioning and clamping integration, can be applicable to heavy material and space limited scene, and it is convenient to operate, structure is reliable.

Description

Technical Field

[0001] This utility model relates to the field of workpiece assembly technology, and in particular to an expansion-type positioning pin. Background Technology

[0002] In the assembly processes of machinery, automotive, and aerospace industries, locating pins are key components for achieving precise positioning of materials to be assembled, and their function directly affects assembly efficiency and quality. Traditional locating pins are typically cylindrical and can only perform a single hole positioning function. If material clamping is required, additional auxiliary components such as process bolts are often needed, leading to cumbersome assembly procedures. Currently, in heavy material assembly scenarios, where workpieces are heavy and subjected to complex forces, relying solely on traditional locating pins for positioning can easily cause material displacement. Additional clamping devices are needed to ensure assembly accuracy, which not only increases the number of operation steps but also extends the operation time.

[0003] In the prior art, Chinese patent CN208595132U discloses an expandable pin, including a pin body with expansion holes on both sides. Expansion plates are movably connected inside the expansion holes. A fixing seat is fixedly installed on one side of each expansion plate, and a pressing block is fixedly installed on one side of each fixing seat. Toothed plates are fixedly installed on the outer walls of the two pressing blocks on opposite sides, and threaded grooves are formed on the inner walls of the two pressing blocks on opposite sides. This expandable pin achieves positioning through a design where an expansion screw drives the expansion plates to expand outwards, thus solving to some extent the problem of excessively high hole precision requirements in traditional cylindrical pins.

[0004] While the aforementioned pins can solve the problem of excessively high hole precision requirements of traditional cylindrical pins, they still have the following shortcomings in practical use: First, these pins can only perform a positioning function and cannot apply clamping force to heavy materials. In suspended assembly or confined spaces, the problem of difficulty in securing materials remains. Second, these pins use a manual rotating handle with a striking block for installation, which is difficult to operate in confined spaces and cannot withstand the load of heavy materials. Third, these pins lack a dedicated clamping design in their structure, failing to meet the stability and reliability requirements for assembling heavy materials. Furthermore, in precision assembly fields such as aerospace, assembly space is often extremely limited. The hammer-in installation method is not only inefficient but may also lead to installation deviations due to insufficient operating space. Utility Model Content

[0005] The purpose of this invention is to overcome the shortcomings of existing expansion pins, such as the inability to apply clamping force to heavy materials, difficulty in adapting to narrow spaces, and the existence of installation deviations, and to provide an expansion positioning pin.

[0006] This utility model is achieved through the following technical solution: an expansion-type positioning pin includes a pin body, one end of which is provided with a positioning boss, and the other end of which is rotatably fitted with a bushing capable of axial displacement. A stepped structure is formed between the positioning boss and the pin body, and between the bushing and the pin body. The pin body has an axially connected mounting groove and an expansion groove inside. The mounting groove corresponds to the positioning boss, and its diameter is larger than that of the expansion groove. An expansion column capable of interference fit with the expansion groove is movably disposed inside the mounting groove. A coaxial screw is connected to the end of the expansion column near the expansion groove, and the end of the screw away from the expansion column can pass through the pin body and the bushing. A sealing platform is provided at the end of the bushing away from the pin body. A threaded through hole is formed at the axis of the sealing platform, and the sealing platform is screwed to the screw through the threaded through hole.

[0007] When the bushing is rotated, the threaded through hole of the sealing platform is screwed to the screw, and the rotation of the bushing will drive the screw to move axially. The screw pulls the expansion column to move in the mounting groove. When the expansion column moves from the mounting groove with a larger diameter into the expansion groove with a smaller diameter, due to the interference fit between the expansion column and the expansion groove, the expansion column squeezes the pin body to expand outward. At the same time, the positioning boss and the stepped structure of the bushing clamp the material on both sides, realizing the positioning and clamping functions.

[0008] This locating pin converts rotational motion into axial tension through the screw connection between the screw and the bushing, avoiding the traditional installation method of hammering. It is suitable for space-constrained scenarios. The expansion column and expansion groove are interference-fitted, so that the expansion column squeezes the pin body to expand outward, ensuring the stability of the material. This solves the problem that existing expansion pins can only locate but cannot clamp heavy materials.

[0009] A further improvement of this utility model is that both the pin and the positioning boss are combined structures. The pin includes multiple sub-pins with a fan-shaped cross-section, and the positioning boss includes multiple sub-bodies with a fan-shaped cross-section corresponding to the number of sub-pins. The multiple sub-pins are evenly arranged circumferentially, and the sub-bodies are integrally set at the ends of the corresponding sub-pins. The two ends of the multiple sub-pins are respectively connected to a fixed end cap, and the fixed end cap away from the sub-bodies is provided with a through hole corresponding to the screw.

[0010] The aforementioned modular structure allows the pin to be disassembled into independent sector units, facilitating individual replacement after wear and reducing maintenance costs. Compared to integral expansion plates, the sub-pins are stronger and can withstand heavy material loads. Furthermore, the uniform distribution of the sub-pins ensures symmetrical expansion force, improving positioning accuracy.

[0011] A further improvement of this utility model is that each of the sub-pins has an arc-shaped mounting groove and an arc-shaped expansion groove connected along the axial direction on its inner side. The position of the arc-shaped mounting groove corresponds to the sub-boss, and the diameter of the arc-shaped mounting groove is greater than the diameter of the arc-shaped expansion groove.

[0012] The above-mentioned combination design of arc grooves avoids uneven expansion caused by machining errors of a single groove. Compared with the straight fit between the expansion screw and the threaded groove in the existing expansion pin, the arc structure can disperse stress, reduce pin deformation, and improve the reliability of this positioning pin.

[0013] A further improvement of this utility model is that an expansion gap is formed between two adjacent sub-pins; and an expansion guide groove corresponding to the expansion gap is provided on each fixed end cap.

[0014] The aforementioned expansion guide groove design solves the problem of uncontrolled expansion direction caused by the lack of a guiding structure in the expansion plate of existing expansion pins, ensuring uniform expansion of the pin body and improving positioning accuracy; the expansion gap design enables the pin body to be elastically deformable, adapting to positioning holes of different diameters and enhancing the applicability of this positioning pin.

[0015] A further improvement of this utility model is that a tapered guide surface is provided at the connection between the mounting groove and the expansion groove; and a guide ball head is integrally provided at one end of the expansion column near the expansion groove.

[0016] The aforementioned tapered guide surface and guide ball head cooperation reduces the resistance to the movement of the expansion column, making the operation of the rotating bushing less strenuous, especially suitable for tool operation in space-constrained scenarios; compared with the rigid contact between the expansion screw and the threaded groove in existing expansion pins, this design reduces mechanical wear and extends the service life of the device.

[0017] A further improvement of this utility model is that the sealing platform has a hexagonal structure.

[0018] The aforementioned hexagonal design is compatible with standardized tools, solving the problem of low efficiency in manually rotating the handle in expansion pins. It enables mechanized operation and improves installation efficiency. At the same time, tool operation is more stable than manual operation, and can precisely control the expansion force, avoiding damage to parts caused by excessive expansion.

[0019] A further improvement of this utility model is that a limit baffle is provided at the end of the expansion column away from the expansion groove.

[0020] The design of the aforementioned limiting baffle avoids the problem of the expansion bolt being unable to reset due to excessive withdrawal in the existing expansion pin, ensuring that this positioning pin can be reused; at the same time, the anti-detachment design improves the safety of this positioning pin and prevents the expansion column from accidentally falling off under heavy material load, causing assembly failure.

[0021] A further improvement of this utility model is that the positioning boss has a conical structure, and the narrow end of the positioning boss is far away from the pin.

[0022] Compared to the flat expansion plate in existing expansion pins, the above-mentioned conical structure has a self-guiding function when inserted into the positioning hole, reducing the difficulty of installation.

[0023] As can be seen from the above technical solutions, the beneficial effects of this utility model are: 1. This locating pin integrates positioning and clamping functions through structural innovation, effectively reducing assembly steps. The locating pin drives the expansion column to move via the rotation of the bushing, allowing the stepped boss on the outer side of the pin to simultaneously clamp and position heavy materials with the positioning boss. This combines two traditional processes into a single operation, significantly shortening processing time. Simultaneously, the stepped structure of the positioning boss and bushing creates a bidirectional clamping force, preventing the easy displacement of heavy materials and improving assembly stability.

[0024] 2. The combination of the locating pin body and hexagonal head bushing design balances structural strength and ease of operation. The pin body is connected by countersunk screws, and the expansion gap and guide groove ensure even distribution of expansion force, allowing it to withstand greater loads and facilitating individual replacement after wear. The hexagonal sealing platform at the rear of the bushing is compatible with tools such as pneumatic triggers, which not only reduces the difficulty of operation in space-constrained areas but also allows for precise control of expansion force, effectively avoiding errors and inefficiencies associated with manual operation.

[0025] 3. This locating pin features a self-guiding design with a tapered locating boss, facilitating insertion into the material positioning hole. The limit baffle and screw connection ensure stable transmission of the expansion column, preventing it from falling out. Furthermore, this locating pin does not require a hammer block for installation, making it easy to operate in suspended or confined spaces. In addition, the axial movement of the expansion column allows for adaptability to different hole diameters, providing a wide range of applications. Attached Figure Description

[0026] To more clearly illustrate the technical solution of this utility model, the drawings used in the description will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a structural schematic diagram of a specific embodiment of the present utility model.

[0028] Figure 2 This is a cross-sectional view of a specific embodiment of the present utility model.

[0029] Figure 3 This is an exploded view of a specific embodiment of this utility model.

[0030] Figure 4 This is a schematic diagram of the expansion column and screw in a specific embodiment of this utility model.

[0031] Figure 5 This is a structural schematic diagram of the pin and positioning boss in a specific embodiment of this utility model.

[0032] In the diagram: 1. Pin body; 101. Mounting groove; 102. Expansion groove; 103. Conical guide surface; 104. Sub-pin body; 105. Arc-shaped mounting groove; 106. Arc-shaped expansion groove; 107. Expansion gap; 2. Positioning boss; 201. Sub-bore; 3. Bushing; 4. Sealing platform; 401. Threaded through hole; 5. Expansion column; 501. Guide ball head; 502. Limiting baffle; 6. Screw; 7. Fixed end cap; 701. Expansion guide groove; 702. Through hole; 8. Countersunk screw; 9. Step structure. Detailed Implementation

[0033] To make the objectives, features, and advantages of this utility model more apparent and understandable, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings of the specific embodiments. Obviously, the embodiments described below are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this patent, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this patent.

[0034] Now refer to Figures 1-5 The following is a description of a specific embodiment: The present invention provides an expansion-type positioning pin, comprising a pin body 1. One end of the pin body 1 is provided with a positioning boss 2, and the other end of the pin body 1 is rotatably fitted with an axially movable bushing 3. Step structures 9 are formed between the positioning boss 2 and the pin body 1, and between the bushing 3 and the pin body 1. The pin body 1 has an axially connected mounting groove 101 and an expansion groove 102 inside. The position of the mounting groove 101 corresponds to the positioning boss 2, and the mounting groove 102... The diameter of groove 101 is larger than the diameter of expansion groove 102; an expansion column 5 that can be interference-fitted with expansion groove 102 is movably arranged inside the mounting groove 101. A coaxial screw 6 is connected to one end of the expansion column 5 near the expansion groove 102, and the end of the screw 6 away from the expansion column 5 can pass through the pin 1 and the bushing 3; a sealing platform 4 is provided at the end of the bushing 3 away from the pin 1. A threaded through hole 401 is opened at the axis of the sealing platform 4, and the sealing platform 4 is screwed to the screw 6 through the threaded through hole 401.

[0035] When the bushing 3 is rotated, the screw rod 6 is screwed into the threaded through hole 401 of the sealing platform 4. The rotation of the bushing 3 will drive the screw rod 6 to move axially. The screw rod 6 pushes the expansion column 5 to move in the mounting groove 101. When the expansion column 5 enters the expansion groove 102 with a smaller diameter from the mounting groove 101 with a larger diameter, the expansion column 5 squeezes the pin 1 to expand outward due to the interference fit between the expansion column 5 and the expansion groove 102. At the same time, the positioning boss 2 and the stepped structure of the bushing 3 clamp the material on both sides, realizing the positioning and clamping functions.

[0036] This positioning pin, through the screw connection between the screw 6 and the bushing 3, can convert rotational motion into axial thrust, avoiding the traditional installation method of hammering, and is suitable for space-constrained scenarios. Through the interference fit between the expansion column 5 and the expansion groove 102, the expansion column 5 can squeeze the pin body 1 to expand outward, ensuring the stability of the material and solving the problem that existing expansion pins can only position but cannot clamp heavy materials.

[0037] Specifically, refer to Figure 3 and Figure 5 Both the pin 1 and the positioning boss 2 are composite structures. The pin 1 includes three sub-pins 104 with fan-shaped cross-sections, and the positioning boss 2 includes three sub-bosses 201 with fan-shaped cross-sections. The three sub-pins 104 are evenly arranged circumferentially, and the three sub-bosses 201 are integrally set at the ends of the corresponding sub-pins 104. The two ends of the three sub-pins 104 are connected to a fixed end cap 7 by countersunk screws 8, and a through hole 702 corresponding to the screw 6 is opened on the fixed end cap 7 away from the sub-bosses 201. When the three sub-pins 104 and the three sub-bosses 201 are combined, the three sub-pins 104 form a complete pin 1, and the three sub-bosses 201 form a complete positioning boss 2.

[0038] Three sub-pins 104 are connected to the fixed end cap 7 via countersunk screws 8, forming a complete pin 1. When the expansion column 5 pushes the sub-pins 104 outward, the sub-pins 104 can expand radially, and the through hole 702 of the fixed end cap 7 provides movement space for the screw 6. After expansion, the sub-pins 104 expand outward, and at the same time, the combined sub-boss 201 and the stepped structure of the bushing 3 clamp the material.

[0039] The above-mentioned combined structure allows the pin 1 to be disassembled into independent sector units, which are easy to replace individually after wear and reduce maintenance costs. Compared with the integral expansion plate, the sub-pin 104 has higher strength and can withstand heavy material loads. The uniform distribution of the sub-pin 104 ensures symmetrical expansion force and improves positioning accuracy.

[0040] Specifically, refer to Figure 2 , 35. Each of the sub-pins 104 has an arc-shaped mounting groove 105 and an arc-shaped expansion groove 106 connected along the axial direction on its inner side. The position of the arc-shaped mounting groove 105 corresponds to the sub-boss 201, and the diameter of the arc-shaped mounting groove 105 is larger than the diameter of the arc-shaped expansion groove 106. When the three sub-pins 104 are combined, the three arc-shaped mounting grooves 105 form a complete mounting groove 101, and the three arc-shaped expansion grooves 106 form a complete expansion groove 102.

[0041] The arc-shaped mounting groove 105 and arc-shaped expansion groove 106 of each sub-pin 104 combine to form a complete mounting groove 101 and expansion groove 102. The expansion column 5 moves within the arc-shaped mounting groove 105, and when it enters the arc-shaped expansion groove 106, the guiding effect of the arc-shaped structure causes the expansion column 5 to uniformly push the sub-pin 104 outward to expand.

[0042] The above-mentioned combination design of arc grooves avoids uneven expansion caused by machining errors of a single groove. Compared with the straight fit between the expansion screw and the threaded groove in the existing expansion pin, the arc structure can disperse stress, reduce the deformation of the pin body 1, and improve the reliability of this positioning pin.

[0043] Specifically, refer to Figure 2 and Figure 4 A tapered guide surface 103 is provided at the connection between the mounting groove 101 and the expansion groove 102; a guide ball head 501 is integrally provided at one end of the expansion column 5 near the expansion groove 102.

[0044] The tapered guide surface 103 of the mounting groove 101 and the expansion groove 102 cooperates with the guide ball head 501 of the expansion column 5. When the expansion column 5 enters the expansion groove 102 from the mounting groove 101, the tapered surface guides the guide ball head 501 to transition smoothly, reducing frictional resistance.

[0045] The cooperation between the tapered guide surface 103 and the guide ball head 501 reduces the resistance to the movement of the expansion column 5, making the operation of the rotating bushing 3 easier and especially suitable for tool operation in space-constrained scenarios. Compared with the rigid contact between the expansion screw and the thread groove in the existing expansion pin, this design reduces mechanical wear and extends the service life of the device.

[0046] In one embodiment, reference Figure 3 and Figure 5 An expansion gap 107 is formed between two adjacent sub-pins 104; each fixed end cap 7 is provided with an expansion guide groove 701 corresponding to the expansion gap 107.

[0047] The expansion gap 107 between adjacent sub-pins 104 provides room for expansion. The expansion guide groove 701 of the fixed end cover 7 corresponds to the expansion gap 107, guiding the sub-pins 104 to expand in a preset direction and preventing deviation during expansion.

[0048] The design of the expansion guide groove 701 mentioned above solves the problem of uncontrolled expansion direction caused by the lack of a guide structure in the expansion plate of the existing expansion pin, ensuring uniform expansion of the pin body 1 and improving positioning accuracy; the design of the expansion gap 107 enables the pin body 1 to be elastically deformable, adapting to positioning holes of different diameters and enhancing the applicability of this positioning pin.

[0049] In one embodiment, reference Figure 1 The sealing platform 4 has a hexagonal structure.

[0050] The hexagonal structure of the sealing platform 4 can quickly rotate the bushing 3 using tools such as wrenches and pneumatic wrenches, transmitting the rotational force to the screw 6 and driving the expansion column 5 to move.

[0051] The aforementioned hexagonal design is compatible with standardized tools, solving the problem of low efficiency in manually rotating the handle in expansion pins. It enables mechanized operation and improves installation efficiency. At the same time, tool operation is more stable than manual operation, and can precisely control the expansion force, avoiding damage to parts caused by excessive expansion.

[0052] In one embodiment, reference Figure 2 and Figure 4 A limit baffle 502 is provided at the end of the expansion column 5 away from the expansion groove 102.

[0053] The limiting baffle 502 of the expansion column 5 restricts the movement range of the expansion column 5 when the screw 6 rotates in the opposite direction, preventing the expansion column 5 from coming out of the mounting groove 101.

[0054] The design of the aforementioned limiting baffle 502 avoids the problem of the expansion bolt being excessively withdrawn in the existing expansion pin, which causes the expansion plate to be unable to reset, ensuring that this positioning pin can be reused; at the same time, the anti-detachment design improves the safety of this positioning pin and prevents the expansion column 5 from accidentally falling off under heavy material load, causing assembly failure.

[0055] In one embodiment, reference Figure 2 and Figure 5 The positioning boss 2 has a conical structure, and the narrow end of the positioning boss 2 is far away from the pin 1.

[0056] The narrow end of the tapered positioning boss 2 is first inserted into the positioning hole. As the pin 1 expands, the tapered surface fits against the hole wall, generating a radial clamping force. At the same time, the stepped structure of the positioning boss 2 abuts against the material surface, achieving positioning and clamping.

[0057] Compared to the flat expansion plate in existing expansion pins, the above-mentioned conical structure has a self-guiding function when inserted into the positioning hole, reducing the difficulty of installation.

[0058] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An expansion-type positioning pin, comprising a pin body (1), characterized in that, One end of the pin (1) is provided with a positioning boss (2), and the other end of the pin (1) is rotatably fitted with a bushing (3) capable of axial displacement. A stepped structure (9) is formed between the positioning boss (2) and the pin (1), and between the bushing (3) and the pin (1). The pin (1) has an axially connected mounting groove (101) and an expansion groove (102) inside. The mounting groove (101) is positioned corresponding to the positioning boss (2), and the diameter of the mounting groove (101) is larger than the diameter of the expansion groove (102). An expansion column (5) that can be interference-fitted with an expansion groove (102) is provided inside the groove (101). The end of the expansion column (5) near the expansion groove (102) is connected to a coaxial screw (6), and the end of the screw (6) away from the expansion column (5) can pass through the pin (1) and the bushing (3) in sequence. A sealing platform (4) is provided at the end of the bushing (3) away from the pin (1). A threaded through hole (401) is provided at the axis of the sealing platform (4), and the sealing platform (4) is screwed to the screw (6) through the threaded through hole (401).

2. The expansion-type positioning pin according to claim 1, characterized in that, Both the pin (1) and the positioning boss (2) are combined structures. The pin (1) includes multiple sub-pins (104) with a fan-shaped cross-section. The positioning boss (2) includes multiple sub-bodies (201) with a fan-shaped cross-section corresponding to the number of sub-pins (104). The multiple sub-pins (104) are evenly arranged in the circumferential direction. The sub-bodies (201) are integrally set at the end of the corresponding sub-pin (104). The two ends of the multiple sub-pins (104) are respectively connected to a fixed end cap (7). The fixed end cap (7) away from the sub-bodies (201) is provided with a through hole (702) corresponding to the screw (6).

3. An expansion dowel according to claim 2, wherein, Each of the sub-pins (104) has an arc-shaped mounting groove (105) and an arc-shaped expansion groove (106) connected along the axial direction on its inner side. The position of the arc-shaped mounting groove (105) corresponds to the sub-boss (201), and the diameter of the arc-shaped mounting groove (105) is greater than the diameter of the arc-shaped expansion groove (106).

4. An expansion dowel according to claim 2, wherein, An expansion gap (107) is formed between two adjacent sub-pins (104).

5. An expansion dowel according to claim 4, wherein, Each of the fixed end caps (7) is provided with an expansion guide groove (701) corresponding to the expansion gap (107).

6. An expansion dowel according to claim 1, wherein, A tapered guide surface (103) is provided at the connection between the mounting groove (101) and the expansion groove (102).

7. An expansion dowel according to claim 1, wherein The expansion column (5) is integrally provided with a guide ball head (501) at one end near the expansion groove (102).

8. An expansion dowel according to claim 1, wherein, The sealing platform (4) has a hexagonal structure.

9. An expansion dowel according to claim 1, wherein, A limit baffle (502) is provided at the end of the expansion column (5) away from the expansion groove (102).

10. The expansion dowel of claim 1, wherein, The positioning boss (2) has a conical structure, and the narrow end of the positioning boss (2) is far away from the pin (1).

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