Reuseable single groove rivet system and method

1. A reusable single groove pull riveting system including a single groove rivet bolt, and a mating collar,

wherein said single groove rivet bolt comprises a head and a shank, said shank comprising a cylindrical portion, a threaded portion and a single groove tail structure which are joined in sequence,

said mating collar comprises a flange and a circular tube portion,

said collar is to be installed on the threaded portion of the bolt,

wherein characteristics of the system are:

a) said short tail is a single groove structure, including a smooth profile single pull groove portion and a raised pull tooth portion;

b) the ratio of the width of said single pull groove to the length of the short tail is 0.4-0.5;

c) the cross sectional area of said single groove is circular, and the ratio of the outer diameter between the smallest cross sectional area and the largest cross sectional area is 0.7-0.9;

d) said short tail has a lead-in angle between 12° and 20°;

e) the collar flange has axial force indicating projection structures on a front face, said projection structures are evenly distributed in radial directions;

f) the collar is heat treated entirely and thoroughly and different strengths can be obtained through a combination of different heating temperatures and cooling rates.

2. The reusable single groove pull riveting system according to claim 1 , wherein said single groove rivet bolt has an annular load relief groove at the juncture of the head and the cylindrical shank portion.

3. The reusable single groove pull riveting system according to claim 1 , wherein said single groove rivet bolt and collar have a ratio between the diameter of the threaded shank portion, φD 1 , and the internal hole diameter of the collar, φD 2 , of 0.95-0.99.

4. The reusable single groove pull riveting system according to claim 1 , wherein said collar has spherical projecting axial force indicators on the front face of the collar flange, and after the collar is installed, the gap between an end face of the flange and a joint member can be detected to determine whether joint is tightly secured or not.

5. The reusable single groove pull riveting system according to claim 1 , wherein the threaded shank portion of said single groove rivet bolt is a plurality of external threads around a circumference of the shank, the surface of the thread form of said external threads is a curved surface, and there is a cylindrical root portion between adjacent threads.

6. The reusable single groove pull riveting system according to claim 5 , wherein said thread form of said single groove rivet bolt comprises a front half tooth and a rear half tooth, wherein the front half tooth has an elevation angle β which is smaller than a projection profile of the rear half tooth, said front half tooth has an elevation angle β of 45°; and the ratio between the width and the pitch of said front half tooth is 0.29-0.35.

7. A tool for installing and removing the reusable single groove pull riveting system according to claim 1 , comprising an installation system and a removal system, wherein the installation system includes a hydraulic station, an oil hose, a driving device and a tool set, said hydraulic station connecting the driving device with the oil hose, said driving device connecting said tool set for installation,

wherein said tool set includes an anvil and an elastic collet, wherein said anvil is a round tube having a cavity and a wall and is fixed with the driving device, said elastic collet is inside the round tube cavity of the anvil, said elastic collet comprises a plurality of circumferentially arranged clamping strips, and outer ends of the clamping strips are gripper teeth in a shape mating tail groove contour, said driving device has a driving rod connected onto the collet, and

said removal system includes a gun body member, a turning tool member, a guiding and positioning member, and a pneumatic/electric motor member.

8. A method of installing a single groove rivet bolt by using the tool according to claim 7 , comprising the following steps:

1) S 101 : Placing the rivet bolt through openings in joint members, rotating the collar onto the bolt and locating it on the thread portion;

2) S 102 : Locating the short tail in mouth of the elastic collet and letting the gripping teeth of the elastic collet contact the short tail;

3) S 103 : Starting the hydraulic station; under the action of a driving rod, the elastic collet moves into the anvil cavity; under the action of the anvil wall the elastic collet gripping teeth clamp the single pull groove of the bolt, circumferentially engaging the groove;

4) S 104 : Continuing to move the elastic collet inwards inside the anvil, wherein the front end of the anvil contacts the front end of the round tube portion of the collar, the anvil applies axial pressure on the collar so the flange presses tightly against the joint members, when the axial force reaches a preset value, spherical projections indicating the axial force are flattened, the anvil continues to move along the collar to radially extrude the barrel of the collar locking the collar into the thread grooves of the bolt;

5) S 105 : Switching the oil flow route inside the hydraulic station, and the elastic collet is restored under the action of the driving rod;

6) S 106 : Completing the installation, restoring the system, and stopping the hydraulic station from running.

9. The method according to claim 8 , wherein the joint members are plates or workpieces.

10. A method of removing a single groove rivet bolt by using the tool according to claim 7 , comprising the following steps:

1) S 201 : Locating and securing the guiding and positioning member of the removal system on the extruded portion of the collar to effect the position locating and guiding before removal;

2) S 202 : Depressing power button and holding it down, holding a handle and the gun body member tightly, feeding forward with proper force to start the first stage of cutting; removing 2-5 mm axially from deformed circular tube portion of the collar so the cutting tool structure can position and guide itself; stopping cutting and removing the guiding and positioning member;

3) S 203 : Starting the second stage of cutting, wherein the cutting tool structure guides and positions itself, continuing cutting until the flange of the collar is reached;

4) S 204 : Using a hammer to gently knock the rivet bolt until it backs out of the mounting hole, and completing removal of the riveting fasteners.