Single-groove and short-tail pulling rivet and erection method thereof

Abstract

Provided is a single-groove and short-tail pulling rivet and an erection method thereof, and the pulling rivet comprises a single groove and a short tail having a broached groove with a continuous and smooth cambered surface, and is characterized by easy manufacturing, low cost and convenient erection. The broached groove is an arc surface with three sections of different radiuses, which solves stress concentration and sticking of a single-groove and short-tail rivet during riveting, and allows a claw of a riveting machine to be engaged to the best position automatically. The tooth profile of a locking groove section of the rivet is a curve combining an arc and a straight line, which greatly improves fastening force. In a word, the invention solves insufficient clamping degree of the short tail, seizing during riveting, blocking of the broached groove, failed riveting, shortage and loss of tightness of existing short-tail pulling rivets, and meets the performance and reliability requirements of the fastening systems for rolling stocks.

Claims

1. A rivet consisting of a rivet and a collar, wherein the rivet comprises a rivet head, a polished rod, a locking groove section, and a tail section connected in sequence, wherein the collar comprises a flange and a sleeve, and the collar is configured to be arranged on the locking groove section, wherein the tail section comprises a broached groove having a curved surface adjacent to a tail tooth, wherein a profile of the curved surface along an axial direction of the rivet consists of arc c having a radius of Rc, arc b having a radius of Rb, and arc a having a radius of Ra, and Ra<Rc<Rb, wherein, in the collar, a thickness of the flange is M, and a length of the sleeve is N, and a ratio between M and N is in the range of 0.15 to 0.4, and a front end face of the collar flange has a waveform pattern.

2. The rivet according to claim 1, wherein the locking groove section of the rivet has a continuous thread, the continuous thread has a pitch of n, a first flank having a width of t, a second flank having a width of m, and a thread depth of h, wherein a ratio between t and n is in the range of 0.4 to 0.5, a ratio between m and n is in the range of 0.3 to 0.4, and a ratio between h and n is in the range of 0.25 to 0.3.

3. A method for installing the rivet according to claim 1, comprising: 1) passing the rivet through a mounting hole of a riveted part and screwing the collar onto the locking groove section of the rivet; 2) sleeving a claw of a riveting machine onto the tail section of the rivet, changing an inner diameter of the claw using an anvil and an oil cylinder; and pushing the claw against the tail portion until the tail portion comes into contact with a locating surface of the claw; 3) pulling the claw away from the tail section to separate the locating surface of the claw from the tail section until a profiling part of the claw engages the broached groove of the tail section of the rivet; 4) applying a force along the axial direction to the riveted part continuously by the riveting machine so as to push the anvil.

Description

(4) BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a structural drawing of the single-groove and short-tail pulling rivet, i.e. graphical representation of step 1 of the erection method.

(2) FIG. 2 is a single-piece graph of the collar 2 in FIG. 1.

(3) FIG. 3 is a single-piece graph of the rivet 1 in FIG. 1.

(4) FIG. 4 is an enlarged drawing of local part I in FIG. 3, i.e. a front view of the broached groove 1.4 with a continuous and smooth curve.

(5) FIG. 5 is an enlarged drawing of local part II in FIG. 3, i.e. an enlarged drawing of the tooth of the locking groove section 1.3.

(6) FIG. 6 is a graphical representation of step 2 of the erection method.

(7) FIG. 7 is a graphical representation of step 3 of the erection method.

(8) FIG. 8 is a graphical representation of step 4 of the erection method.

(9) FIG. 9 is a graphical representation of step 9 of the erection method.

(10) FIG. 10 is a single-piece graph of an existing multi-groove and short-tail rivet.

(11) FIG. 11 is a single-piece graph of an existing single-groove and short-tail rivet.

(12) FIG. 12 is an enlarged view of local part In in FIG. 11, i.e. front view of the broached groove of existing single-groove and short-tail pulling rivet 1.4n.

(13) FIG. 13 is an enlarged view of local part IIm in FIG. 10, i.e. tooth profile of the locking groove section 1.3m of existing multi-groove and short-tail rivet.

(5) DESCRIPTION OF THE PREFERRED EMBODIMENT

(14) See FIG. 1, the single-groove and short-tail pulling rivet in the example consists of a rivet 1 and a collar 2. See FIG. 3, the rivet 1 comprises a rivet head 1.1, a polished rod 1.2, a locking groove section 1.3 and a short tail connected in order from front to back. See FIG. 2, the collar 2 comprises a flange 2.1 and a sleeve 2.2 from front to back. See FIG. 1, the collar 2 is arranged on the locking groove section 1.3. New design of the invention is as follows: 1) See FIG. 3, the short tail is a single-groove short tail consisting of a broached groove 1.4 with a continuous and smooth curve, and a short tail tooth 1.5; i.e. the single-groove short tail consists of a broached groove 1.4 with a continuous and smooth curve, and a short tail tooth 1.5. 2) See FIG. 4, the broached groove 1.4 with a continuous and smooth curve is designed such that a smooth and continuous cambered surface is formed by three sections of arcs c, b and a with different radii in order from front to back, radii of arcs corresponding to the three sections of cambered surfaces c, b and a are Rc, Rb and Ra respectively, and Ra<Rc<Rb. 3) See FIG. 2, thickness of the flange 2.1 of the collar 2 is M, length of the sleeve 2.2 is N, and M/N=0.15-0.4. 4) See FIG. 2, the front end face of the flange of the collar 2 is provided with a waveform pattern 2.3. 5) See FIG. 5, the tooth profile of the locking groove section 1.3 of the rivet is a smooth curve combining an arc with a straight line (<), and the projection length ratio meets t:n=0.4-0.5; m:n=0.3-0.4; h:n=0.25-0.3; wherein n is teeth space, t is rear half tooth width, m is front half tooth width and h is tooth depth.

(15) The erection method of the single-groove and short-tail pulling rivet comprises the following steps: 1) See FIG. 1, passing the rivet through a mounting hole 3a of a riveted part 3 from front to back, and screwing the collar onto the locking groove section of the rivet from back to front (double-sided riveting); 2) See FIG. 6, sleeving a claw 4.1 of a riveting machine onto the short tail end of the rivet, changing inner diameter of the claw under the action of an anvil 4.2 and an oil cylinder by loosening, grasping and loosening again the claw; and pushing the claw with a hand to move forward axially in relation to the short tail end until the rear end face 1.5A of the short tail comes into contact with a locating surface 4A of the claw; 3) See FIG. 7, starting the riveting machine 4, moving the claw thereof backward due to an axial force, separating the locating surface 4A of the claw from the rear end face 1.5A of the short tail, and sliding a claw profiling part 4C toward the rear end face 1.5A of the short tail along a cambered surface of the broached groove 1.4 due to the axial force until the profiling part 4C is engaged with the broached groove 1.4 of the rivet and clamps the rivet; 4) See FIG. 8, applying an axial force to the riveted part continuously by the riveting machine so that the anvil 4.2 and the claw 4.1 do relative motion, and moving the rivet backward due to a clamping force; axially pushing and extruding the anvil 4.2 forward the collar, compressing the collar by the riveted part 3 tightly and locking the collar on the locking groove section 1.3 of the rivet in a deformed way; and 5) See FIG. 9, when the riveting machine reaches the preset pressure, hydraulically reversing the riveting machine, pushing the claw pushed back by the drive of a hydraulic cylinder, moving the anvil backward and exiting, and returning the profiling part 4C to initial state, and removing the riveting machine from the rivet to completing riveting.