Blind rivet

Abstract

The application discloses a blind rivet which is composed of a rivet core, a rivet body and a rivet sleeve. The rivet core is composed of a rivet core head, a smooth rod knurl, a smooth rod, a locking groove, a fracture groove, a combination groove and a rivet core tail which are sequentially arranged on a rivet core rod. The inner side surface of the rivet core head is an inwardly recessed inclined surface which is inclined to the shaft center, and the included angle between the radial line of the inner side surface and the axial line of the rivet core is less than 90 degrees. The rivet body is composed of a rivet body rod and a rivet body head, and has an axial through rivet body hole. The diameter of the rivet body head is greater than that of the rivet body rod. The rivet sleeve is a cylindrical drum structure, and a circumferential convex part is arranged in the middle of the axial surface of the rivet sleeve, and the two sides of the convex part are gradually changed into a reduced diameter inclined surface. The blind rivet can effectively lock the rivet core and the rivet sleeve after riveting, avoids the rivet core from falling off after installation, reduces the fastening performance of the connecting pair, obtains higher fastening performance and improves the reliability of the blind rivet connection. The components of the blind rivet are pre-assembled into a whole through interference fit, are not easy to separate and lose, and are convenient for transportation, storage and use of the product.

Description

Technical Field

[0001] This invention belongs to the field of riveting technology, and particularly relates to a blind rivet, which belongs to the riveting category (B21J) and fastener category (F16B) of metal machining. Background Technology

[0002] A blind rivet is a fastener that allows for installation by inserting it into a mounting hole from only one side of the connected parts. Existing blind rivets generally consist of two parts: a shank (rivet core) and a body. After assembling the shank and body, installation and riveting can be performed. During installation, the operator inserts the assembled blind rivet into the mounting hole. A riveting tool grips the tail of the shank, moving the rivet outward and compressing the body to form a blind head on the blind side. Ultimately, the shank may or may not break, completing the riveting. The formation of a blind head on the blind side is the most fundamental characteristic that distinguishes blind rivets from fasteners that require installation from both sides.

[0003] Existing products and technologies have shortcomings in the locking and fastening of the rivet body and rivet shank. The rivet shank is the main load-bearing component of the entire blind rivet, and it plays a decisive role in the fastening performance of the entire blind rivet. In existing products, the rivet shank and rivet body cannot be effectively locked together, which will cause the rivet core to fall out of the inner hole of the rivet body, seriously affecting the reliability of the blind rivet connection.

[0004] Patent application CN101641524B expands the nail body on the blind side to form a blind rivet head by using a rivet core head, and then pulls it off at the fracture groove of the rivet core. This technology does not have an effective locking measure between the nail body and the rivet core after riveting.

[0005] Patent application CN102187104B describes a method in which a bulge is formed in the workpiece by applying tension to the shank after the shank and the shank are combined, and the shank is installed in the workpiece. However, this method does not provide an effective measure to prevent the shank from falling off between the shank and the shank.

[0006] Patent application CN105179430B forms a spiral groove and an annular groove on the nail body. During installation, a bulge with a petal-shaped blind side force-bearing area is generated on the blind side of the workpiece. The spiral groove has a depth that gradually increases toward the head of the nail sleeve to promote the initial formation of the bulge toward the head. However, this technology does not form an effective measure to prevent the nail rod from falling off between the nail body and the nail shank.

[0007] Patent application CN106795903A provides a blind rivet with a cutting edge at the head of the rivet and different wall thicknesses in the rivet body. During riveting, the thin wall of the rivet body is cut open to form a lace-shaped blind rivet head, and the thick wall of the rivet body is squeezed into the fixing groove to play a certain role in fixing the rivet shank. Summary of the Invention

[0008] This invention discloses a blind rivet to address the shortcomings of existing technologies. The purpose of this invention is to provide a blind rivet that, after riveting, effectively locks the rivet core and rivet sleeve together, preventing the rivet core from detaching after installation and thus avoiding reduced fastening performance of the connection pair, thereby achieving higher fastening performance and improving the reliability of blind rivet connections.

[0009] This invention is achieved through the following technical solution:

[0010] A blind rivet, characterized in that it consists of a rivet core, a rivet body and a rivet sleeve fitted onto the rivet core;

[0011] The nail core is a rod-shaped structure, consisting of a nail core head, a smooth knurled rod, a smooth rod, a locking groove, a fracture groove, a combination groove, and a nail core tail arranged sequentially on the nail core rod; the inner surface formed by the nail core head is an inwardly inclined surface that slopes towards the axis, and the angle between the radial line of the inner surface and the axial line of the nail core is less than 90 degrees.

[0012] The nail body has a cylindrical structure, consisting of a nail body shank and a nail head, and has an axially penetrating nail body hole; the diameter of the nail head is larger than that of the nail body shank;

[0013] The rivet sleeve has a cylindrical drum-shaped structure. A circumferential protrusion is provided in the middle of the axial surface of the rivet sleeve, and the two sides of the protrusion form a continuous slope that gradually narrows towards both ends.

[0014] When the blind rivet of the present invention is in a free and unsecured installation state, the knurled outer diameter of the rivet core is larger than the inner diameter of the rivet body hole and is assembled with an interference fit with the rivet body. The outer diameter of the combination groove of the rivet core is larger than the inner diameter of the rivet sleeve and smaller than the inner diameter of the rivet body hole and is assembled with an interference fit with the rivet sleeve.

[0015] Furthermore, the outer diameter of the nail core head > the outer diameter of the knurled smooth rod > the outer diameter of the combined groove > the outer diameter of the locking groove > the outer diameter of the fracture groove; the distance between the knurled smooth rod and the nail core head is 0.3 to 1 times the smooth rod diameter; the knurled smooth rod length is 0.6 to 2 times the smooth rod diameter; the locking groove length is 1 to 3 times the nail sleeve length; and the combined groove length is 0.5 to 1 times the nail sleeve length.

[0016] Furthermore, the inner diameter of the nail body is larger than the outer diameter of the nail core combination groove and smaller than the knurled outer diameter of the nail core smooth rod. The outer diameter of the nail body rod is not greater than the outer diameter of the nail core head. The outer diameter of the nail body head is 1.5 to 2.5 times the outer diameter of the nail body rod. The total length of the nail body is not greater than the distance between the nail core head and the combination groove.

[0017] Furthermore, the inner diameter of the rivet sleeve is smaller than the outer diameter of the rivet core combination groove and larger than the outer diameter of the rivet core locking groove. The total length of the rivet sleeve is between 0.6 and 1 times the nominal diameter of the rivet, and the inclination angle from the middle of the rivet sleeve to both ends is 15 to 30 degrees.

[0018] Furthermore, the tail of the nail core is provided with a ring groove for the riveting tool to grasp and apply riveting force.

[0019] Furthermore, the circumferential protrusion of the nail sleeve ring and the bevels on both sides transition into a radially symmetrical structure, and the bevel transition along the axial direction is either a straight line transition or a circular arc transition.

[0020] The blind rivet of this invention consists of a rivet core, a rivet body, and a rivet sleeve. The outer diameter of the knurled smooth shank on the rivet core is larger than the inner diameter of the hole in the rivet body, so as to assemble the rivet core and the rivet body together by means of an interference fit; the outer diameter of the combination groove is larger than the inner diameter of the hole in the rivet sleeve but smaller than the inner diameter of the hole in the rivet body, so that the rivet body can pass through freely and can also be assembled with the rivet core and the rivet sleeve by means of an interference fit.

[0021] The junction between the rivet head and the smooth rod is a recessed slope with a certain inward angle. The inner surface formed by the rivet head is a recessed slope inclined towards the axis, and the angle between the radial line of the inner surface and the axial line of the rivet head is less than 90 degrees. Making the inner surface of the rivet head an inclined slope towards the axis prevents the expansion of the rivet end face, which is beneficial for the rivet to form a blind rivet head on the blind side during the riveting process.

[0022] The tail of the rivet is used by the riveting tool to grip the part for applying riveting force. The rivet head is flat and round, which is beneficial for mass production; the outer diameter of the rivet head can be 1.5 to 2.5 times the outer diameter of the rivet shank, which can connect small holes on the blind side inner plate and large holes on the operating side outer plate during riveting, reducing the hole accuracy requirements of the connected parts and improving the installation economy of blind rivets.

[0023] The rivet sleeve is an axially symmetrical structure with a larger diameter in the middle and smaller diameters at both ends. The connection from the middle bulge to the two ends can be a straight line or a rounded transition. The advantage of the symmetrical structure is that there is no need to distinguish between the two ends of the rivet sleeve during assembly, which reduces the production cost of blind rivets. Moreover, when riveting, the blind rivet can be installed by starting riveting from either end of the rivet sleeve.

[0024] The rivet core is the main load-bearing component of the blind rivet. Current technology does not effectively fasten the rivet core, which leads to the risk that the rivet core may fall out of the rivet body after installation, affecting the reliability of blind rivet installation.

[0025] The blind rivet of this invention effectively locks the rivet core and rivet sleeve together after riveting, preventing the rivet core from falling off after installation and thus avoiding a decrease in the fastening performance of the connection pair, achieving higher fastening performance and improving the reliability of the blind rivet connection. The components of the blind rivet are pre-assembled into a whole through interference fit, making them less prone to separation and loss, and facilitating the transportation, storage, and use of the product. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the components of a blind rivet;

[0027] Figure 2 This is a schematic diagram of the core of a blind rivet;

[0028] Figure 3 This is a schematic diagram of the blind rivet body;

[0029] Figure 4 This is a schematic diagram of a blind rivet sleeve;

[0030] Figure 5 This is a schematic diagram showing the completed blind rivet riveting process;

[0031] Figures 6 to 9 This is a schematic diagram of the blind rivet riveting process.

[0032] In the diagram, 1 is the nail core, 11 is the nail core head, 12 is the recessed bevel, 13 is the smooth knurled bar, 14 is the smooth bar, 15 is the locking groove, 16 is the fracture groove, 17 is the combination groove, and 18 is the tail of the nail core.

[0033] 2 is the nail body, 21 is the nail body shaft, 22 is the nail head, and 23 is the nail hole;

[0034] 3 is the nail sleeve, 31 is the protrusion, 32 is the bevel transition, 33 is the bevel angle, and 34 is the nail sleeve hole;

[0035] 4 and 5 are the connected parts, 6 is the anvil for pressing the nail sleeve, and 7 is the claw for clamping the tail of the nail core. Detailed Implementation

[0036] The present invention will be further described below with reference to specific embodiments. These specific embodiments are further explanations of the principles of the present invention and are not intended to limit the present invention in any way. Any technology that is the same as or similar to the present invention does not exceed the scope of protection of the present invention.

[0037] Refer to the attached diagram.

[0038] The blind rivet of the present invention comprises a rivet core 1, a rivet body 2, and a rivet sleeve 3. The rivet core is composed of a rivet core head 11, an indented bevel 12, a smooth rod 14, a smooth rod knurling 13, a locking groove 15, a fracture groove 16, a combination groove 17, and a rivet core tail 18 in sequence. The rivet body includes a rivet body head 22, a rivet body rod 21, and a through rivet body hole 23. The rivet sleeve includes a drum-shaped protrusion 31 in the axial middle of the rivet sleeve, a bevel transition 32 from the drum-shaped protrusion 31 to both ends, and a through rivet sleeve hole 34 along the axis. The external surface presents a transversely symmetrical structure that is larger in the middle and smaller at both ends.

[0039] Figure 1 A side sectional view of the blind rivet of the present invention is shown. As shown in the figure, the blind rivet consists of a rivet core 1, a rivet body 2, and a rivet sleeve 3. The rivet body and the rivet sleeve are assembled with the rivet core by an interference fit, which facilitates the transportation, storage and use of the product.

[0040] Figure 2The rivet core 1 is one of the components of the blind rivet of this invention. 11 is the rivet core head, 12 is the recessed bevel, 13 is the smooth knurled shank, 14 is the smooth shank, 15 is the locking groove, 16 is the fracture groove, 17 is the combination groove, and 18 is the rivet core tail. The outer diameter dimensions of the rivet core 1 have the following relationship: outer diameter of the rivet core head 11 > outer diameter of the smooth knurled shank 13 > outer diameter of the combination groove 17 > outer diameter of the locking groove 15 > outer diameter of the fracture groove 16. This series of outer diameter dimensions facilitates the assembly of the rivet body and the rivet sleeve. One end of the rivet head 11 is tapered, which is beneficial for installation. The recessed bevel 12 prevents the end face of the rivet body 21 from turning out and failing to form a blind rivet head. There is a certain gap between the smooth rivet knurling 13 and the rivet head 11, which is beneficial for knurling. The smooth rivet knurling 13 can ensure the assembly quality with the rivet body 2 while avoiding excessive interference fit force affecting the riveting. The locking groove 15 ensures consistent fastening performance within a reasonable thickness range of the riveting. The combination groove 17 ensures the assembly quality with the rivet sleeve 3 while avoiding excessive interference fit force affecting the riveting. The tail of the rivet head 18 is the clamping part of the claw 7.

[0041] Figure 3 This is the rivet body 2 of the blind rivet of the present invention. 21 is the rivet shank, 22 is the rivet head, and 23 is the rivet hole. The inner hole 23 is larger than the outer diameter of the rivet core assembly groove 17 and smaller than the outer diameter of the knurled rivet core shank 13, allowing the rivet body and rivet core to be assembled together via an interference fit. The outer diameter of the rivet shank 21 is not larger than the outer diameter of the rivet core head 11, ensuring that the rivet core head and rivet shank can be inserted into the same mounting hole. The outer diameter of the rivet head 22 is 1.5 to 2.5 times the outer diameter of the rivet shank, allowing connection between small holes in the blind side inner plate and large holes in the operating side outer plate during riveting, reducing the accuracy requirements for the holes of the connected parts and improving the economic efficiency of blind rivet installation.

[0042] Figure 4 This invention relates to a blind rivet sleeve 3. 31 is a protrusion, 32 is a beveled transition, 33 is the bevel angle, and 34 is the sleeve hole. The inner diameter of the sleeve hole 34 is smaller than the outer diameter of the rivet core assembly groove 17 but larger than the outer diameter of the rivet core locking groove 15. This relationship ensures both the quality of the sleeve and the rivet core assembly and feasible riveting performance. The sleeve has an axially symmetrical structure with a larger diameter in the middle and smaller diameters at both ends. The connection from the middle protrusion 31 to the two ends can be a straight line or a rounded transition. The advantage of this symmetrical structure is that it eliminates the need to distinguish between the two ends of the sleeve during assembly, reducing the production cost of the blind rivet. Furthermore, during riveting, the blind rivet can be installed by starting riveting from either end of the sleeve. The inclination angle 33 from the middle of the sleeve to both ends is 15 to 30 degrees to obtain good fastening performance.

[0043] like Figure 6As shown, after assembling the rivet core 1, rivet body 2, and rivet sleeve 3, they are inserted from one side into the pre-prepared holes of the connected parts 4 and 5. Due to the larger outer diameter of the rivet head, the pre-drilled hole diameter on the connected part 5 can be larger than the hole on the connected part 4, reducing the assembly accuracy of the connected parts 4 and 5 and thus saving manufacturing costs. The tail of the blind rivet is then inserted into the riveting tool, and the rivet tail engages with the chuck, ready for riveting.

[0044] like Figure 7 As shown, after the riveting switch is activated, the chuck 7 begins to move backward and clamps the tail of the rivet, moving together with it. The anvil 6 remains stationary and presses against the rivet sleeve and rivet body to prevent them from moving backward, causing the end of the rivet body to bend and deform under the pressure of the rivet head and rivet sleeve, expanding to form a blind rivet head.

[0045] like Figure 8 As shown, under the action of the jaw 7 clamping the rivet and continuously moving backward, the anvil 6 squeezes and deforms the rivet sleeve, and locks the metal of the rivet sleeve into the locking groove of the rivet core, forming a reliable and permanent fastening connection.

[0046] like Figure 9 As shown, after the chuck 7 clamps the rivet and moves backward, causing the anvil 6 to squeeze the rivet sleeve metal into the rivet core locking groove, the anvil end face abuts against the rivet head end face, and finally pulls the rivet core off from the rivet core fracture groove, completing the riveting installation process.

Claims

1. A blind rivet, characterized in that: It consists of a nail core, a nail body fitted inside the nail core, and a nail sleeve; The nail core is a rod-shaped structure, consisting of a nail core head, a smooth knurled rod, a smooth rod, a locking groove, a fracture groove, a combination groove, and a nail core tail arranged sequentially on the nail core rod; the inner surface formed by the nail core head is an inwardly inclined surface that slopes towards the axis, and the angle between the radial line of the inner surface and the axial line of the nail core is less than 90 degrees. The nail body has a cylindrical structure, consisting of a nail body shank and a nail head, and has an axially penetrating nail body hole; the diameter of the nail head is larger than that of the nail body shank; The sleeve is a cylindrical drum-shaped structure. A circumferential protrusion is provided in the middle of the axial surface of the sleeve, and the two sides of the protrusion form a continuous slope that gradually narrows towards both ends. In the free and unsecured installation state of the blind rivet, the knurled outer diameter of the rivet core is larger than the inner diameter of the rivet body hole and is assembled with an interference fit with the rivet body. The outer diameter of the rivet core's combination groove is larger than the inner diameter of the rivet sleeve and smaller than the inner diameter of the rivet body hole, and is assembled with an interference fit with the rivet sleeve. The outer diameter of the nail core head is greater than the outer diameter of the knurled smooth rod, the outer diameter of the combined groove, the outer diameter of the locking groove, and the outer diameter of the fracture groove. The distance between the knurled smooth rod and the nail core head is 0.3 to 1 times the diameter of the smooth rod. The knurled smooth rod is 0.6 to 2 times the diameter of the smooth rod. The length of the locking groove is 1 to 3 times the length of the nail sleeve, and the length of the combined groove is 0.5 to 1 times the length of the nail sleeve.

2. The blind rivet according to claim 1, characterized in that: The inner hole of the nail body is larger than the outer diameter of the nail core combination groove and smaller than the knurled outer diameter of the nail core smooth rod. The outer diameter of the nail body rod is not greater than the outer diameter of the nail core head. The outer diameter of the nail body head is 1.5 to 2.5 times the outer diameter of the nail body rod. The total length of the nail body is not greater than the distance between the nail core head and the combination groove.

3. The blind rivet according to claim 2, characterized in that: The inner diameter of the rivet sleeve is smaller than the outer diameter of the rivet core combination groove and larger than the outer diameter of the rivet core locking groove. The total length of the rivet sleeve is between 0.6 and 1 times the nominal diameter of the rivet. The inclination angle from the middle of the rivet sleeve to both ends is 15 to 30 degrees.

4. The blind rivet according to claim 3, characterized in that: The tail of the nail core is provided with a ring groove for the riveting tool to grip and apply riveting force.

5. The blind rivet according to claim 3, characterized in that: The circumferential protrusion of the rivet and the inclined surfaces on both sides of the rivet ring are radially symmetrical, and the axial transition of the inclined surfaces is either a straight line transition or a circular arc transition.

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