Self-locking blind rivet

Abstract

This utility model belongs to the field of blind rivet technology, specifically relating to a self-locking blind rivet. The self-locking blind rivet provided by this utility model includes a core rod, on which an expansion sleeve, a locking sleeve, and a driving sleeve are sequentially fitted. The core rod has a head at its front end, a truncated cone section (smaller at the front and larger at the rear) in the middle, and a breakage groove at the rear. The expansion sleeve includes an expansion section, a rigid section, and a flange with an expansion surface. During riveting, the core rod moves backward, causing the head to push the expansion section to expand radially, while a locking gap is formed between the truncated cone section and the expansion surface. The driving sleeve includes a breakable plugging tube and a first support ring. When the connection breaks, the pushing end face at the front end of the plugging tube pushes the locking sleeve to fill the locking gap, achieving self-locking and anti-retraction of the core rod. This rivet solves the problem of easy loosening of traditional blind rivets under vibration through structural innovation, and has advantages such as strong vibration resistance, reliable connection, and simple operation.

Description

Technical Field

[0001] This utility model belongs to the field of blind rivet technology, specifically relating to a self-locking blind rivet. Background Technology

[0002] Rivets, as a classic mechanical fastener, are widely used in many industrial fields such as aerospace, rail transportation, automobile manufacturing, electronic communications, and building decoration due to their ease of operation and reliable connection. In particular, blind rivets, with their unique advantage of single-sided riveting, play an irreplaceable role in enclosed or hard-to-reach spatial structures, greatly improving assembly efficiency.

[0003] Currently, the technology of ordinary blind rivets is quite mature and can meet the fastening requirements under normal working conditions. However, in specific application scenarios such as high-speed vehicles, mechanical equipment subjected to alternating loads for a long time, and large structural components subject to continuous vibration, more stringent requirements are placed on the vibration resistance, long-term stability, and reliability of the connection points. After riveting, the core of an ordinary blind rivet and the rivet body are mainly kept relatively fixed by friction, lacking effective mechanical interlocking. Under long-term, high-intensity vibration environments, this friction may gradually weaken, leading to the risk of the core loosening and retraction, which in turn reduces the connection preload and may even cause structural loosening, creating potential safety hazards. Utility Model Content

[0004] To address the shortcomings of existing technologies, this utility model provides a self-locking pull rivet.

[0005] The purpose of this invention is to provide a novel blind rivet solution that can maintain a stable and reliable connection over a long period of time in a high-vibration environment, while also featuring a simple structure, convenient installation, and controllable cost.

[0006] The self-locking pull rivet provided by this utility model includes a core rod, on which an expansion sleeve, a locking sleeve, and a driving sleeve are sequentially fitted from the front end to the rear end. The core rod has a head at the front end and a truncated cone section with a smaller radial dimension at the front and a larger radial dimension at the rear in the middle. A breakage groove is provided behind the truncated cone section. The expansion sleeve includes an expansion section, a rigid section, and a flange sequentially from the front end to the rear end. The rear end of the flange forms a support end face, and an expansion surface is formed at the junction of the support end face and the inner wall. When the core rod moves backward, the head pushes the expansion section to expand radially, and at the same time, the truncated cone section moves to the corresponding expansion surface, thereby forming an annular locking gap between the outer surface of the truncated cone section and the expansion surface. The driving sleeve includes a filling tube and a first support ring integrally connected to the front end of the filling tube. The first support ring and the filling tube are detachably connected to separate under a preset axial pressure. The front end of the filling tube forms a pushing end face. After the filling tube separates from the first support ring, the pushing end face pushes the locking sleeve to fill the locking gap, restricting the core rod from retracting.

[0007] As a further optimization, a support section is provided on the core rod behind the rod head. The outer diameter of the support section is matched with the inner diameter of the expansion section to form radial support for the expansion section.

[0008] As a further optimization, the inner circumferential surface of the locking sleeve is provided with multiple anti-disengagement teeth arranged along its axial direction, and each anti-disengagement tooth is arranged in a ring shape along the inner circumferential surface of the locking sleeve.

[0009] As a further optimization, each anti-detachment tooth has a forward-facing slope with an angle of 8° to 30° with respect to the axis, and a rearward-facing end face with an angle of 80° to 90° with respect to the axis.

[0010] As a further optimization, a guide ramp is provided at the front end of the outer circumference of the locking sleeve, which is formed by circumferential oblique cutting at the front end of the locking sleeve.

[0011] As a further optimization, the drive sleeve also includes a second support ring integrally connected to the rear end of the packing tube, the second support ring being used to abut against the head of the rivet gun.

[0012] As a further optimization, when the second support ring moves forward to abut against the first support ring, the locking sleeve completely fills the locking gap.

[0013] As a further optimization, the rear end surface of the core rod is provided with anti-slip texture.

[0014] As a further optimization, the wall thickness of the rigid section is greater than that of the expansion section, so that the axial compressive force borne by the rigid section is greater than that of the expansion section.

[0015] As a further optimization, the breakage groove is designed to break when the tensile force on the core rod reaches a preset threshold, so as to remove the excess tail of the core rod after riveting.

[0016] Beneficial effects Compared with the prior art, the self-locking pull rivet provided by this utility model can effectively prevent the core rod from retracting after riveting, achieve a stable self-locking effect, and significantly improve the vibration resistance and loosening resistance of the connection structure. At the same time, its drive sleeve has the functions of support and filling during the riveting process, which simplifies the operation steps, improves the riveting efficiency and reliability, and is suitable for various scenarios that require high strength and durability fixation. Attached Figure Description

[0017] Figure 1 This is a structural schematic diagram of the self-locking pull rivet of this utility model.

[0018] Figure 2 This is a schematic diagram of the core rod structure.

[0019] Figure 3 This is a schematic diagram of the expansion sleeve.

[0020] Figure 4 This is a schematic diagram of the drive sleeve.

[0021] Figure 5 This is a schematic diagram of a cross-section of one side wall of the locking ring.

[0022] Figure 6 This is a schematic diagram of the locking process of a self-locking pull-out rivet.

[0023] In the diagram, 1. Core rod; 2. Expansion sleeve; 3. Locking sleeve; 4. Drive sleeve; 11. Rod head; 12. Support section; 13. Frustum section; 14. Breakaway groove; 15. Anti-slip texture; 21. Expansion section; 22. Rigid section; 23. Flange; 231. Support end face; 232. Expansion surface; 31. Guide ramp; 32. Anti-tooth removal; 41. Stuffing tube; 42. First support ring; 43. Second support ring; 411. Pushing end face. Detailed Implementation

[0024] The present invention is further illustrated by the following embodiments, which are intended to more clearly illustrate the technical solution of the present invention, and should not be construed as a limitation. Example

[0025] This embodiment provides a self-locking pull rivet, such as Figures 1 to 5 As shown, it includes a core rod 1, on which an expansion sleeve 2, a locking sleeve 3, and a driving sleeve 4 are sequentially fitted from front to rear. For ease of description, all subsequent descriptions of "front" and "rear" directions are based on this fitting order.

[0026] The core rod 1 has a rod head 11 at its front end, and a support section 12 and a frustoconical section 13 from the front end to the rear end. A breakage groove 14 is also provided behind the frustoconical section 13. The expansion sleeve 2 includes an expansion section 21, a rigid section 22, and a flange 23 from the front end to the rear end. The rigid section 22 can withstand a greater axial compressive force than the expansion section 21. In this embodiment, the strength difference is achieved by the rigid section 22 having a wall thickness greater than that of the expansion section 21. In other embodiments, this can also be achieved by setting a deformation guide groove in the expansion section 21. During riveting, when the core rod 1 is pulled backward, the rod head 11 pushes the expansion section 21 of the expansion sleeve 2 backward, causing the expansion section 21 to contract axially and expand radially. At this time, a bidirectional blocking structure is formed at both ends of the rigid section 22. The front blocking is the radially expanded expansion section 21, and the rear blocking is the flange 23. One or more layers of plates to be fixed, sleeved on the outside of the rigid section 22, can be firmly clamped by this bidirectional blocking.

[0027] The rear end surface of flange 23 forms a support end face 231, which abuts against the front end of drive sleeve 4. Simultaneously, the junction of the support end face 231 and the inner wall of flange 23 has an expansion surface 232, formed by removing some material from the inner wall of expansion sleeve 2 near the rear end, resulting in a rearwardly expanding trumpet shape. The core rod 1 has a frustum section 13 in the middle, with a radial dimension that gradually decreases from a small front end to a large rear end. When the core rod 1 is pulled backward and drives expansion sleeve 2 to complete expansion, the frustum section 13 synchronously moves to a position corresponding to the expansion surface 232 of expansion sleeve 2. At this time, an annular locking gap is formed between the outer surface of the frustum section 13 and the expansion surface 232. The locking gap provides space for the locking sleeve 3 to fill. When the locking sleeve 3 fills into the locking gap, the outer surface of the frustum section 13 will be squeezed by the locking sleeve 3, thereby restricting the core rod 1 from moving forward and back, and finally achieving the effect of the rivet not loosening after being riveted and being highly effective in shock resistance.

[0028] The drive sleeve 4 is located behind the locking sleeve 3. It includes a central stuffing tube 41, a first support ring 42 integrally connected to the front end of the stuffing tube 41, and a second support ring 43 integrally connected to the rear end of the stuffing tube 41. The inner side of the rear end of the first support ring 42 is connected to the outer side of the front end of the stuffing tube 41. Due to the small connection area and weak connection, it can break after being subjected to a preset compressive force, thus separating the stuffing tube 41 from the first support ring 42. At the same time, the outer diameter of the stuffing tube 41 is equal to or close to the inner diameter of the first support ring 42, allowing the separated stuffing tube 41 to smoothly enter the interior of the first support ring 42.

[0029] In the initial stage of riveting, the unbroken drive sleeve 4 can withstand a certain compressive force, and the head of the rivet gun can abut against the rear end of the drive sleeve 4. At this time, pulling the core rod 1 backward can drive the expansion section 21 to complete the expansion. After the expansion section 21 expands, continuing to pull the core rod 1 backward will cause the tension of the core rod 1 to increase significantly, thereby increasing the axial pressure on the drive sleeve 4. When the pressure exceeds the bearing limit of the weak connection, the connection between the first support ring 42 and the filling tube 41 breaks. The front end of the broken filling tube 41 enters the first support ring 42 forward, and its front end push face 411 will push the locking sleeve 3 forward simultaneously, squeezing the locking sleeve 3 into the aforementioned locking gap to complete the locking action. This structural design of the drive sleeve 4 has dual functions. In the early stage, it can be used as a support component to pull the core rod 1, and in the later stage, it can be transformed into a filling tool to push the locking sleeve 3 to fill the locking gap, which greatly improves the integration and practicality of the rivet structure.

[0030] In this embodiment, the second support ring 43 at the rear end of the drive sleeve 4 abuts against the head of the rivet gun to achieve stable force application. Simultaneously, after the filling tube 41 separates from the first support ring 42, the second support ring 43 can limit the forward movement of the filling tube 41, ensuring that the locking sleeve 3 is filled to the appropriate depth of the locking gap. Specifically, it is configured such that when the second support ring 43 moves forward to abut against the first support ring 42, the locking sleeve 3 is just filled to the required preset depth; this design is preferred. In other embodiments, the second support ring 43 can be omitted, and the rear end of the filling tube 41 can be directly abutted against the head of the rivet gun.

[0031] In this embodiment, as a preferred solution, the outer diameter of the part of the core rod 1 located behind the support section 12 is smaller than that of the support section 12, while the inner diameter of the rigid section 22 of the expansion sleeve 2 is smaller than that of the outer diameter of the expansion section 21. When the core rod 1 is pulled backward until the rear end face of the support section 12 reaches or approaches the front end face of the rigid section 22, the backward movement of the core rod 1 is restricted. At this time, continuing to pull the core rod 1 will further increase the axial tension of the core rod 1, thereby causing the axial pressure borne by the drive sleeve 4 to increase synchronously, and finally achieving the breakage at the connection between the filling tube 41 and the first support ring 42, and smoothly entering the filling and locking stage.

[0032] In this embodiment, as a preferred solution, the outer peripheral wall of the support section 12 can form radial support for the expansion section 21 sleeved on it. Its outer diameter is set to be basically consistent with the inner diameter of the expansion section 21. Since the expansion section 21 needs to achieve radial expansion under axial compression, the presence of the support section 12 can restrict the expansion section 21 from deforming in the direction of radial size reduction (i.e., inward) during the deformation process, thereby reliably guiding the expansion section 21 to expand outward in a preset direction.

[0033] In this embodiment, as a preferred embodiment, a guide ramp 31 is provided at the front end of the outer peripheral surface of the locking sleeve 3. The guide ramp 31 is formed by circumferentially obliquely cutting the front end of the locking sleeve 3, which allows the locking sleeve 3 to enter the locking gap more smoothly when squeezed by the packing tube 41. In other embodiments, the guide ramp 31 may be omitted.

[0034] In this preferred embodiment, the inner circumferential surface of the locking sleeve 3 is further provided with multiple anti-loosening teeth 32 arranged along its axial direction. Each anti-loosening tooth 32 is annular along the inner circumferential surface of the locking sleeve 3, and each anti-loosening tooth 32 has a forward-facing slope with an angle of 8° to 30° with the axis, and a rearward-facing end face with an angle of 80° to 90° with the axis. This structural design does not affect the smooth entry of the locking sleeve 3 into the locking gap, and after the locking sleeve 3 is filled in, the anti-loosening teeth 32 and the outer surface of the frustum section 13 are squeezed and engaged to effectively suppress the possibility of the locking sleeve 3 loosening from the locking gap, significantly improving the structural stability after the self-locking core-pulling rivet is riveted, making it suitable for use scenarios with strong vibration.

[0035] In this embodiment, as a preferred solution, anti-slip texture 15 is provided on the rear end surface of the core rod 1 to facilitate the rivet gun's secure clamping.

[0036] Figure 6 This demonstrates the complete riveting process of the self-locking pop rivet, in which... Figure 6 (a) is the initial state, at which point the rear end of the core rod 1 is clamped in the head of the rivet gun, but the core rod 1 has not yet been pulled backward; Figure 6 (b) is the state after the core rod 1 is pulled in the first stage. The expansion sleeve 2 completes radial expansion under axial compression. At this time, the filling tube 41 of the drive sleeve 4 and the first support ring 42 are still connected as a whole. Figure 6 (c) is the state after the core rod 1 is pulled in the second stage. The filling tube 41 of the drive sleeve 4 has been completely separated from the first support ring 42, and the filling tube 41 has pushed the locking sleeve 3 into the locking gap to achieve stable riveting. Figure 6 (d) shows the state after riveting is completed. At this time, the head of the rivet gun has been removed and the drive sleeve 4 has been removed from the rivet body.

[0037] After the locking action is completed, continue to pull the core rod 1. When the tension on the core rod 1 reaches the withstand threshold of the breakage groove 14, the core rod 1 will break at the breakage groove 14, thereby removing the excess tail of the core rod 1 after riveting, ensuring that the appearance of the rivet after riveting is neat and without any unexpected protrusions.

[0038] The above embodiments are exemplary and are intended to illustrate the technical concept and features of this utility model, so that those skilled in the art can understand the content of this utility model and implement it accordingly. They should not be construed as limiting the scope of protection of this utility model. All equivalent changes or modifications made in accordance with the spirit and essence of this utility model should be included within the scope of protection of this utility model.

Claims

1. A self-locking pull rivet, characterized in that, The device includes a core rod (1), on which an expansion sleeve (2), a locking sleeve (3), and a driving sleeve (4) are sequentially fitted from front to rear. The core rod (1) has a rod head (11) at its front end and a truncated cone section (13) with a smaller radial dimension at the front and a larger radial dimension at the rear. A pull-out groove (14) is provided behind the truncated cone section (13). The expansion sleeve (2) includes an expansion section (21), a rigid section (22), and a flange (23) sequentially from front to rear. A support end face (231) is formed at the rear end of the flange (23), and an expansion surface (232) is formed at the junction of the support end face (231) and the inner wall. When the core rod (1) moves backward, the rod head (11) pushes the expansion section (21) to expand radially, and simultaneously... The frustum section (13) moves to the position corresponding to the expansion surface (232), thereby forming an annular locking gap between the outer surface of the frustum section (13) and the expansion surface (232); the drive sleeve (4) includes a stuffing tube (41) and a first support ring (42) integrally connected to the front end of the stuffing tube (41), the first support ring (42) and the stuffing tube (41) are detachably connected to separate under a preset axial pressure; the front end of the stuffing tube (41) forms a push end face (411), after the stuffing tube (41) and the first support ring (42) are separated, the push end face (411) pushes the locking sleeve (3) forward to fill the locking gap, restricting the core rod (1) from retracting.

2. The self-locking pull rivet according to claim 1, characterized in that, The core rod (1) is provided with a support section (12) behind the rod head (11). The outer diameter of the support section (12) is adapted to the inner diameter of the expansion section (21) to form radial support for the expansion section (21).

3. The self-locking pull rivet according to claim 1 or 2, characterized in that, The inner circumferential surface of the locking sleeve (3) is provided with a plurality of anti-detachment teeth (32) arranged along its axial direction, and each anti-detachment tooth (32) is arranged in a ring shape along the inner circumferential surface of the locking sleeve (3).

4. The self-locking pull rivet according to claim 3, characterized in that, Each of the anti-detachment teeth (32) has a slope facing forward at an angle of 8° to 30° with respect to the axis, and an end face facing backward at an angle of 80° to 90° with respect to the axis.

5. The self-locking pull rivet according to claim 1, characterized in that, The locking sleeve (3) has a guide ramp (31) at the front end of its outer peripheral surface, which is formed by oblique cutting at the front end of the locking sleeve (3).

6. The self-locking pull rivet according to claim 1, characterized in that, The drive sleeve (4) also includes a second support ring (43) integrally connected to the rear end of the filling tube (41), the second support ring (43) being used to abut against the head of the rivet gun.

7. The self-locking pull rivet according to claim 6, characterized in that, When the second support ring (43) moves forward to abut against the first support ring (42), the locking sleeve (3) completely fills the locking gap.

8. The self-locking pull rivet according to claim 1, characterized in that, The rear end surface of the core rod (1) is provided with anti-slip texture (15).

9. The self-locking pull rivet according to claim 1, characterized in that, The wall thickness of the rigid section (22) is greater than that of the expansion section (21), so that the axial compressive force borne by the rigid section (22) is greater than that borne by the expansion section (21).

10. The self-locking pull rivet according to claim 1, characterized in that, The pull-off groove (14) is configured to break when the tension on the core rod (1) reaches a preset threshold, so as to remove the excess tail of the core rod after riveting.

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