FR2651283A1 - Internally explosive blind rivet - Google Patents

Abstract

Rivet of the type comprising a cylindrical body made from a malleable metal (1) and ending in a head (3) at one end, the said body (1) including an axial channel (2) in which there is housed a core (8), the said core including means for giving rise, on the one hand, to an explosion in the chamber (12) and, on the other hand, the flaring out of the free end of the body (1) of the rivet which, on the opposite side from the head (3) has a cap provided with two cutting ridges (5).

Description

 The present invention relates to a blind rivet with internal explosion.

 Rivets are known which are placed by inserting the body into a hole previously made in the pliers to be assembled, then, using a special tool, exerting traction on the rod in order to cause the expansion of the ex - free end of the body to make the rivet and the breaking of the rod. These rivets are practical and widely used. All of them, they require two operations: the drilling of the parts to be assembled and the riveting, using a tool provided with drawing means, which does not ensure a tightness of the assembly because the rod of the rivet leaves the axial channel open.

The object of the present invention is to produce a rivet which allows riveting to be carried out while ensuring the seal
The object rivet of the invention is of the type comprising a cylindrical body of malleable metal and terminated by a head at one end, said body comprising an axial channel in which is housed a core, said core comprising means for causing, part internal explosion intended to ensure a violent push, and on the other hand pieces of hard metal to cause 11 blooming of 1 e: rtré-mite free of the body of the rivet.

 According to a constructive detail, the body of the rivet on the opposite side of the head may include a steel cap and having cutting edges for use in a rotary tool as a self-piercing rivet.

 Finally, according to another constructive detail, the head of the rivet is hexagonal and can be inserted in a rotating tool in its self-piercing version.

The invention will now be described in more detail with reference to a particular embodiment given by way of example only and shown in the accompanying drawing, in which
Figure 1 is a sectional view through an axial vertical plane of the rivet according to the invention and in the self-drilling version.

 This rivet is intended to be used with a percussive tool or of the type described in patent of invention n089 10426 of the present applicant and provided with means of printing an electric discharge. The rivet according to the invention comprises a cylindrical body (1) pierced with a blind axial channel (2) and provided with an end terminated by a head (3) preferably hexagonal.

Said channel (2) contains a core (8) and is closed off because it is produced in the form of a blind bore (7) on the opposite side of the head (3) to form an expansion chamber (20). The body (1) can be extended from the opposite side of the head (3) by a cap (4) provided with two cutting edges (5) and strongly crimped to the body (i) by means of the spiral notches (6) .The core (8) is screwed into the axial channel (2) by a self-tapping thread (9) and immobilized by the crimping (21), said core (8) is crossed in the part of the side of the head (3 ), by an electrode or a detonator (10) separated from the mass by the insulator (ii), and opening into an explosion chamber (12), said chamber (12) is closed by a piston (13) having sliding ramps (14) and sliding on an axis (15) integral and axial with the core (8) by a thread (16) on the side of the head of the rivet (3) and ending with an enlarged head (17) hollowed out housings with curved lower ramps (18) intended to receive and guide the bean-shaped pushing pieces (19) having a thinned side intended to operate the deformation and the development of the free part of the body (1), exiting laterally between the end of the core (8) and the enlarged tette (17) and taking support on the wall of the body
The rivet is made of a malleable metal, while the core and the means for developing the rivet are made of hard steel so that they do not crush when exploded.

 In the self-piercing version, when the tette (3) is driven in rotation, it collects the body (1) and the cap (4), owing to the fact that the tip of the cap is applied to the sheet (22) to be drilled, its cutting edges (5) make a hole in it.

When the hole is made (see fig. 2), the tool depending on the version) gives a blow on the detonator or an electric discharge on the electrode (10) causing a spark (23) when it exits into the chamber. explosion (12) and triggering an explosion which exerts a violent thrust on the piston (13) which sliding on the axis (15) and cooperating with the ramps (14) and the housings (18) cause in a lateral movement the parts of push back
(19) in order to practice the deformation of the free part of the body (1), which is compensated by the expansion chamber
(20).

 The deformation of the body of the rivet (1) operating from the inside without any element leaving the axial channel and keeping the whole of the part (7) of the body of the rivet (1), ensures sealing assemblies. In its self-piercing version, the development of the part (7) of the body of the rivet (i) causes the cap (4) to fall (see fig. 2).

 Of course, the invention is not limited to the embodiment which has just been described and shown. Many modifications can be made to it without departing from the scope of the invention.

Claims (1)

 REVEI) lCÂtl0NS  O Rivet of the type comprising a cylindrical body of malleable metal (1) and terminated by a head (3) at one end, said body (1) comprising a blind axial channel (2) in which is housed a core (8), characterized in that it contains means (13, 14, 15, 18, 19) for causing the free end (7) of the body to flourish when an explosion is caused in the explosion chamber (12), which contains an explosive, said free end (7) being closed to form an expansion chamber (20).  20- Rivet, according to claim 1 characterized in that the means (10) causing the explosion are arranged on the part of the core of the outer face of the head (3).  3 - Rivet, according to claims let 2 characterized in that the means causing the explosion (10) are constituted by an insulated electrode opening into the explosion chamber (12).  40- Rivet, according to claims 1 and 2 characterized in that the means causing the explosion (10) consist of a detonator intended to be struck.  5 - Rivet, according to claim 1, and any one of the preceding claims, characterized in that it further comprises a cap (4) securely fixed on the free end (7) of the body (1) by means of spinnaker notches roidal (6) and comprising two cutting edges (5), ensuring when the rivet is rotated, the piercing of the ttle to be assembled then the opening of the part (7) causing the detachment of said cap (4) from the body rivet (1).  6 - Rivet, according to claims 1 and 5 characterized in that the head (3) is hexagonal, to ensure its drive in rotation.  70- Rivet according to claim 1, characterized in that the means causing the blooming of the free end of the body (1) consist of a piston (13) provided with ramps (14) sliding on an axis (15 ) pushed by the force of explosion cooperating with the lower ramps (18) to guide the pushing pieces (19) in lateral movement and causing a push on the internal walls of the axial channel (2)