CA2105122C

CA2105122C - Electro-weldable connecting piece having connection terminals and its method of manufacture

Info

Publication number: CA2105122C
Application number: CA002105122A
Authority: CA
Inventors: Denis Dufour; Martine Brunet
Original assignee: Gaz de France SA
Current assignee: Engie SA
Priority date: 1992-09-01
Filing date: 1993-08-30
Publication date: 2005-08-16
Anticipated expiration: 2013-08-30
Also published as: DE69303441T2; GR3020459T3; DK0586283T3; EP0586283A1; CA2105122A1; ATE140072T1; FR2695173B1; EP0586283B1; JP3495064B2; ES2088648T3; JPH07304102A; DE69303441D1; FR2695173A1

Abstract

Rivet-type assembly piece comprising an ejectable male rivet shank having a widened part at one end; and a conducting elongate female body (5) penetrated by an axial passage (11) where the said shank can be inserted, this body having an intermediate collar (13) delimiting upper and lower sections, this body being produced from a deformable material in order to be crushed. thereby forming a flange (5'b). According to the invention, the piece is characterized in that it is used as an electrical connector for the electrical supply of a conducting piece (21), such as a meshed resistance element. Application to the production of electro-weldable connecting pieces, especially in the gas industry.

Description

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~_ The invention relates to a plastic connecting piece (such as a sleeve or a T-coneection saddl~) inten-ded for joining axially or transversely, and by heat-welding, twa pipes, in particular in the gas industry, the invention relating more particularly to the.improve-ment of the connection terminals of the electrically conducting resistance element with which said connecting device is equipped.
Such a device, which includes, for the heat-welded ZO joining of two polyethylene ~ipes, an electrical heating resistance element consisting of a coiled electrically conducting wire embedded in the thickness of the piece in the vicinity of its internal welding surface, is already known from publications EP-A-0,149,410 or LTS-A-4,684,417.
The welding operation is then carried out by placing opposite each other the pieces to be welded and by connecting the coiled electrical wire to an electrical source (such as a rectified source of alternating cur-rent) which. by the Joule effect, will heat up the resistance element and cause the softening until melting of the plastic surrounding the pieces. ensuring welding under pressure.
Fox the electrical connection of the resistance element, its two wire ends are usually each welded to a connection terminal each often emerging into a well or a cavity, so ~s to be able to constitute two pins which will be able to be plugged in, inside the said w~lls, t~
remavable complementary sockets.
Still within the same field, other types elf resistance element can b~ used.
Thus, publication FR-A-2,654,978 provides the use of a single-wise net or of a grid which can be produced from a stretched metal plate.
However. the e~eternal electrical conaxaction of this net or of this grid rennaix~a the same as the solution mentioned hegeinabove. In, the first case (single-wire net). the two ends of the wine era drawn out in order to ba welded to the aforementioned pins. In the second case (stretched grid). it is advised to use two conducting 2~C3j:~2 _ 2 plates fixed at two opposite ends of the grid, and two conducting joint cables welded on one aide to the said plates and on the other side to the two aforementioned pine.
However, problems of reliability of the welded joints may then occur. There i~ also the r3sk~that the fusion zone of the plastic body can end up damaging these joints. at the moment of the welding.
Furthermore, especially in the case of the use of a monofilar net. all this implies lengthy and tricky implementation operations.
Anather solution is provided in ,A.pplication EP-A-0,2°78,553. In this application, the connection terminals are applied to a connection piece in which a resistance element in the form of. a coiled wire is embedded. These terminals each consist of two complement-ary pieces which are fitted into each other after having been inserted into the cavities provided for this purpose in the connecting piece. The two parts of the one same terminal, which are subjected to two opposed direction forces, are thus suitable for gripping a thin thickness of plastic where the resistance element passes and. once °'clipped together", then establish an electrical contact with this resistance element. However, the use of such terminals necessitates producing tapped holes in the piece in ordsr to ins~rt therein the two complementary components of the terminals. ~n the other hand the fitting of these components one into the other could lead (if the fitting forces are..not very precisely applied).
to a detrimental deformation of the connecting piece.
Taking this into account, the object of the invention is especially to provide a connecting piece whose connection terminals ensure a connection which is reliable and is carried out very rapidly by a simple operation, the electrical joint obtained with the resis-tance element being particularly firm mechanically, without appreciable risk of this resistance element ' tearing or of the puce becoming damaged.
Thus it has been imagined to have recourse to a riveted joint.
of course, the use of rivets is known :Ln mechanical engineering. It is also known, from EP-A-0,010,055, to use a rivet as an electric socket. In this application, a blind rivet is fixed to an electrically conducting solid metal. sheet in order to establish an electrical contact r~rith this metal sheet. This rivet is installed in a known manner by virtue of a pair of tongs exerting on a single side a traction force on the male component of the r~.vet, the female component being 14 held pressed ags.inst the metal sheet.
However, EP-A-0,010,055 does not relate to the field of electro-welding.
This document therefore does not take into account the problems specific to electro-weldable thermoplastic pieces and especially the questions:
a)-of mechanical and thermal. stresses which the resistance element and its joint have to withstand during the welding;
b) -of installation of the said terminals within the piece itself.
With regard to point a), nothing indicates that the riveted joint of EP-A-0,010,055 could be suitable for an electro-weldable device, the more So as document EP-A-0,278,553 invites the use of two-piece electrical terminals, therefore certainly being able, at least slightly, to act one with respect to the other and with respect to the resistance element, if the mechanical stresses due to heating during the welding are too great. It will also be noted that the rivet of EP-A-0, 07.0, OS5 is fixed to a solid plate, and is therefore relatively rigid, whereas the terminals of EPA-0,278,553 are fixed to a coiJ.ed wire.
E~.~rthermore, as regards point b) , if, based on EP-A-0,2?8,553, it is sought to install. instead of terminals hav~.ng fittable components, the rivet described in EP-A~o,010,055, by conventional application, from one side, of a force an its male component (the female component being pressed against the thin layer of plastic enclosing 'the resistance element), this would certainly run the risk of a disastrous deformation of this layer, or indeed of the wire resistance element.
Now, going precisely counter to the teaching that the person skilled in the art would be able to draw from EP-A-0,278,553 and EP-A--0,010,OSS, the invention precisely provides the use of a rivet (and more precisely of its female Component) as an electrical connector for supplying the resistance element of a joint piece for the heat-welded joining especially of polyethylene pipes_ According to vne aspect of the present invention, there is provided a connecting device for connecting two pipes therebetween, said pipes being at least partly made of a heat-weldable thermoplastic material, said device comprising a body made of a heat-weldable thermoplastic material including.
-a resistance element fox heating said thermoplastic material of the body, and welding it with the thermoplastic material of the pipes; and -connection terminals electrically connected to said resistance element and extending through said device body so a~s to emerge outwardly on an outer surface thereof, each terminal comprising a tubular rivet body made of an electrically conductive material, so as to be an electrical connector, said tubular rivet body comprising first and second tubular parts and an integral collar ther2between, the second part extending through an opening zn the resistance element and having its distal portion compacted to corm a flange, the resistance element being held between the flange and the 3Q collar, In practice, the female body of the rivet will ensure its connection function by means of its shaft which will be able to act as a pin. In addition, the connecting device, which is the subject of the present invention, will be able to constitute an electro-weldable sleeve for the substantially coaxial joining of two pipes by heat-welding. This piece will also be able to constitute an electro-weldable branch connector far the transverse joining of the pipes.
Advantageously, and as indicated above, the invention is most particularly applicable if the resistance i5 in the form 5 of a monofilar meshed net, which is particularly sensitive to the stresses which can be induced during the welding.
Another problem which arises is therefore that of the electrical contact to be established with this particular type of resistance element under optimum conditions of effectiveness and in conjunction with the' problems of mechanical stresses mentioned previously.
Hence, a preferred embodiment involves assoc~.ating with each.rivet component engaged through a mesh of the resistance element, means far tearing the covering layer of the said wire at the location of the riveting of the terminal, thus ensuring the electr~.cal contact, the said terminals furthermore being, with the resistance element, partly embedded, by moulding, in the body of the piece. In practice, and preferably, the adopted tearing means will extend around this mesh facing the flange of the terminal. For this purpose, and depending on the size ag the meshes of the net, it will be possible in particular tv use two washers for each rivet, gripping the net tightly between them, one of these washers (which can most particularly be of the "toothed" type).
Finally, taking into account the above, according to a second aspect of the invention there is provided a method of manufacturing a connecting device for Connecting two pipes therebetween, said pipes being at least partly made of a heat-weldable thermoplastic material, said device comprising a body made of a heat-weldable thermoplastic material having a resistance element for heating said thermoplastic material of the body, to weld the thermoplastic material of the pipes and connection terminals, each connection terminal having a tubular rivet body comprising first and second tubular parts and an integral collar therebetween, said method comprising the steps of:

~~1 - riveting each of the connection terminals to the resistance element so that the second tubular part of each connection terminal extends through an opening in the resistance element and has its distal portion compacted to form a flange, the resistance element being held between the flange and the collar; and -over-molding the body of the connecting device onto said connection terminals so that the first tubular part of each connection terminal emerges into an opened cavity of said device body, said cavity opening on an external surface of the device body.
It will be noted that such a manufacturing method has the advantage of being simple to implement, the reliability of the terminals/resistance-element electrical connection virtually preventing any risk of rupture of this connection, during the overmoulding especially. Furthermore, the fixing of the terminals to the resistance element before overmoulding the assembly makes it possible to avoid the possible risks of deformation of the piece which are connected, on installing the terminals on the already-formed body, with its resistance element.
Other characteristics and advantages of the invention will again appear from the more detailed description which follows, given with reference to the_.

210'3 ~~

attached drawings which show, in a non-limiting fashion, embodiment and utilization examples of the invention.
Thus, in these figures:
- Figure 1 shows, in exploded view, the two pieces which can form the basis of the ~1~ctrical connec tion rivet of the inventions - Figure 2 shows the installation of the rivet of Figur~ 1 for the electrical connection of a conducting piece;
- Figure 3 shows the entire Figure 2 once the rivet has been riveted;
~ Figur~ 4 shows the rivet of Figure l, to which has been added two washers, the rivet being in this ease arranged in the position ready to grip a net portion tightly;
- Figure 5 shows a possible embodiment detail of the wire constituting the n8t illustrated in Figure according to the detail V of this same figure;
- Figure 6 shows the entire Figure 4 once the connection piece has been riveted;
- Figure 7 shows a possible conformation of monofilar n~t which can be used in particular on a heat-weldable connecting sleeve;
- Figure 8 is a view of the .net of Figure 7 in th~ direction of the arrow VIII of this same Figure 7t - Figure 9 shows an embodimerat detail of the net, at the location of the r~ference IX of Figure 70 - Figure 7.0 repres~nts. in central longitudinal section, an ~lectro-weldabl~ connecting sleeve equipp~d with the rivetslnet assembly;
- Figure 11 represents another possible embodi-ment of such a net having the appearance of a ring or a crown:
- and Figure 12 is a central longitudinal s~c-tional view of a T-connection saddle ec;uipped with the net in the form of a. rosett~ of Figure 11, h~r~ reprs-sented in a cut-away view.
First of all, Figure 1 shows an ass~mbly piece of the "blind" rivet type~which will therefor~ bs used as an electrical connection terminal.
The device, identified in its entirety by 1, comprises an "ejectable" male rivet stud 2 and an elongate female body 5. It will be noticed that this stud 2 has a shank 3 and a ~ridex~ed part forming the head at one end. R frangible neck portion ~, near the head 9, divided the shank 3 into a proximal portion and a distal portion.
The stud 2 is said to be "ejectable" in that its shank 3 breaks off at the location of the preformed rupture neck 7 and is separated from the head 9 and the body 5, once the latter has been riveted, the stud then being ejected from the riveting apparatus.
Regarding the body 5, this is penetrated by an axial passage 11 of intermediate cross--section ~i between the cross-section ~ of the shank and that d of the head 9 so that only the said shank can be inserted therein.
In addition to this, the body 5 has, at an intermediate location along its axial length, an external. normal collar 13 delimiting a lower tubular section 5a (the longer section) and an upper tubular section Sb (the shorter section) , coaxial one with respect to the other.
Preferably, (and in fact conventionally), the two parts of the piece 1, stud and body, will be produced from metal, such as alum~.niurn typically, being thus electrically conducting and relatively malleable under a force without rupturing.
By Way of embodiment example, the stud 2 will be able to have a length of approximately 40 millimeters with a shank 3 cross-section of the order of 1 millimeter and a head cross-section (_d~) of the order of 2 millimeters. As regards the tubular body 5, this will be able to have a length of approximately 25 millimeters with a cross-section of the lower section Sa of the order of 35 to 40 millimeters and a cross-section of the upp~r section 5b of the order of 25 to 30 millimeters, each section being able to have a length of approximately 15 and 8 millimeters, respectively, Figure 2 shows the piece 1 engaged in an orif~.ce 15 made through an electrically conducting piece 17, such as a metal plate which is to be supplied with electric power via a connection terminal, a role which the piece 1 will play once the ls.tter has been riveted to this plate.
In order to fix the piece 1. the diameter of the orifice will be less than the diameter d, (see Figure 1) of the collar 13 which has been placed just beneath the plate 17, the orifice 15 of which is only penetrated by the upper tubular 10 section 5b.
The shank 3 of stud 2 has been installed through the body 5 in such a way that its head 9 emerges on the side of the upper section 5b.
Once the piece 1 has been thus arranged, it will suffice, 15 in order to fix it, to use a conventional pair of riveting tongs available commercially, such as a pair of tongs of the "FACOM" trade mark (registered trade rnark), model "GESIPR NT
X".
Undex the action of the jaws of this pair of tongs which will exert an axial traction force on the shank 3 in the direction of the arrow 19 of Figure 2, the head 9 will exert a, compressive force on the section 5b which, made from a plastically deformable material, will be squashed from its free upper end in order to form a flange identified by 5'b in Figure 3, the cross-section of this flange then being greater than the cross-section of the orifice 15, thus keepir~g, by means of this riveting operation, the plate 17 between the flange formed and the collar 13.
During this operation, and as indicated hereinabove, the shank 3 will break off at the location of its preformed rupture neck 7, the distal or lower shank part being ejected from one side, the remaining proximal or upper poxtion of this shank and the head 9 being ejected from the other.
In this manner, thexe now only remains, fixed to the plate, a single electrically conducting body 5 whose cylindrical hollow shaft 5a will be able to be used as a pin for the connection to an associated socket, such as, for example. one of the two sockets 2I, 23 illustrated in Figures and 12.
Figure 4 and the following figures illustrate the 5 applicat~.on of the connection terminal of the invention to the electrical connection of a conducting piece produced in the form of a cloth or of a meshed net.
Such a net used on an electro-weldable connect3.ng piece is in particular described in the publication FR-A-2,654,978 10 (corx~espanding Unwed States Patent US-A-5,141, 580) . For any complementary information concerning this net, it will be poss~.ble to refer to these publications, to which the reader is directed for referez~ca.
Thus, Figure 4 represents a net portion having interlaced sections, the net having the particular feature of being preferably produced from a single electrically conducting wire 21 (i.e., ensuring electrical continuity from one end to the other of the network).
The structure of this wire has been recalled in Figure 5, from which it is possible to show that the said wire can in particular consist of a conducting cable 23 (for example made of copper) of a few tenths of a millimeter in diameter coated with a layer or with a film 2S, for example based on polyesteximide, and electrically insulating at least up to a Z5 predetermined temperature (approximately 250°C).
Figure 4 shows the shank 3 inserted into the internal passage 11 of the body 5, in such a way that the head 9 emerges from the side of the section 5b which penetrates one of the meshes of the net, For good integrity of the assembly, two larger-diameter metal washers 2', 29 have been added, one above the net and the other beneath it.
After the riveting has been performed, the net or the corresponding meshed fariric will thus be encountered again, as shown in Figure 6, held tightly between the two washers 27, 29 the flange 5tb holding it a17. tightly together. between it and the collar 13.

rf the wire of the meshing used is of the type of that of Figure 5, it will therefore be necessary to provide, on the ri~ret, rupture means for tearzng, during .

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the riveting, the skin ~5 at this location of the placing of the rivet, so as thus to ensure the electrical con-tact.
These tearing means could, for example, consist of sgrrations made on the '°upper'° surface 13a (see Figure 4) of the collar 13.
FIowever, in this case, it has b~en preferred to use as the washer ~9 a toothed washer which is to ensure the same effect. Thus, these tearing means extend around the mesh penetrated by the terminal, that is to say substantially perpendicular to the shaft 5, between the mesh in c~aestion and the collar 13, facing the flang~ 5'b (or indeed its sid~).
Let us now turn our attention to Figures 7 to 9, in order to describe briefly the usg, on an electro weldable plastic sleev~, of such a meshed net thus connected to the connection terminal 5 of Figure 6, towards each of th$ opposite ends of its wire.
Figures 7 and 8 show the tubular shape, in the form of a cylinder of substantially circular cross-, section, of the net 31 whose two opposite ends of the wire constituting it have been identified by 21a and 21b.
E'igure 9 illustrat~s dial;rammatically the manner in which the °°St°°-shop~d loops of the ware 21 are mutually 25~ interlaced in oxder t0 cOnstitutl9 the meshes of the net, which net is ~naountered agaia arrang~d inside the electro-weldable connecting sleeve 33 in Figure 10.
Except for this resistanc~ element in the form of a n~t 31, which is here arranged with its cylinder axis 31a substantially coincident with the axis 35 of the wide central cylindrical orifice 37 which penetrates right through the sleeve, the letter has, locally, on two opposite sides of its external perimeter. two cavities or wells 39. 41. which are open to the outside and, in this 39 case, are substantially p~rpendicular to the axis 35.
Into each of these cavities egesrges tho free end of one of the two shafts 5a of a conn~ction terminal 5 in accordance with the~inv~ntion. of tours~. each terminal 5 has been riv~ted b~forehand to the resistive net with ~~~~~ 2 - 1, -interposition of the washer 27 and of the toothed washer 29.
Thus arranged, the two shafts 5a will be able to constitute two electrical connecting pins, which are connectable, if care has been taken to give them a suitable length and diameter, with two conventional connecting sockets. such as the sockets 21 and 23, which are themselves each connected to their conducting supply cabl~, respectively 43 and 45.
Figure 10 also shows the two thermowaldable plastic pipes 47, 49 intended to b~ joined together via the sleeve 33. Tn this cas~, these pipes have been arranged coaxially so that their two ends facing each other are inserted quite tightly inside the orifice 37 of the sleeve.
Let us now turn our attention to Figures 11 and 12 in order to show another application of the invention.
First of all, it will b~ possible to notice in Figure 19. that the shape of the conducting net. refer enced in this case by 51, is in t:he form of a flanened ring.
Such a °'resiative ring" can especially be of the type of that described in lFxench Patent Application FR-A-92/04415 filed by the present Applicant on 10th April 3992. Tn other words, the component 51 can be produced from the meshed cylindrical structure of Figures 7 axxd 9 from which a section will have been cut, which section will have been squashed on itself and flattened so as to constitute a double-thickness circular ring.
It is this ring 51. having a single resistive wire which is encountered again in Figure 12.
This figure more generally shows an electro-weldable branch connector 53 for the transverse connect-ing of a pipe 55 with another pipe (not shown).
Ian this case. the piece 53 whose body is produced from a heat-meltable plastic (such as polyethylene), as was the body of the sleeve~33. has a part 57 in the foray of a saddle with yin internal surface 59 forming a cylinder part of semicircular cross-section, so as to be 2~.8~~~ ~~

able to straddle substantially coaxially the pipe 55.
In the vicinity of this internal surface 59, and embedded in its plastic body, the piece 53 encloses the resistiv8 ring 51 which has, of course, a curvature corresponding substantially to that of the saddle 57, the central orifice 61 of this resistive element 5l~surround-ing, at some distance, the passage 63 of the shaft 65, which stands up substantially half way along th~ branch connector, perpendicular to the axis of the pipe 55. Tn practice, and as is known per as, the passage 63 is intended to b~ prolonged by a coaxial orifice 67 enabling the pipe 55 to communicate transversQly with anoth~r pipe which will be installed and correctly connected to the projecting shaft 65.
As before, and substantially in th~ region of thg two ends of its constitu~nt wire, the resis~tiv~ ring 51 is connected to the then-riveted corn~ction terminals 5 preferably with their washers 27, 29.
~s in figure 10, the two terminals 5 stand up in order to emerge into two transwersa external wells 69, 71, each being thus connectabl~ to the removable sockets 21, 23.
In practice, the manufacture of the two pieces 33, 53 will be easy to implement. In order to do this. it will suffice, after having chosen the moat suitable resistance element (such as the :resistive cylinder 31 fQr th~ sl~ev~ 33 and the r~sistivE~ ring 51 for the trans-verse T-connection connectar 53), to fix the two connection terminals 5 bar riveting, taking care to arrange them at th~ two locations making it possible to ensure a current flow such that it runs, from one of the terminals, at least into most of the said resistance element, b~sfor~ reaching the second terminal.
Once this crimping operation has been completed, the resistance slam~nt will then be placed, with its terminals, in a moulding machin~. known per se, and ont~
these terminals will be overmoulded. by injection, the plastic body of the~connecting piece. During this opera tion. the wells 39, 41 or 69. 71 will be produced with, ~~.~W~

panetratin~ through them, the shafts 5a (of cross-section markedly smaller than that of the said wells).
Tt will them suffice to allow the piece to cool until it is completely solidified.

Claims

1. A connecting device for connecting two pipes therebetween, said pipes being at least partly made of a heat-weldable thermoplastic material, said device comprising a body made of a heat-weldable thermoplastic material including:
-a resistance element for heating said thermoplastic material of the body, and welding it with the thermoplastic material of the pipes; and -connection terminals electrically connected to said resistance element and extending through said device body so as to emerge outwardly on an outer surface thereof, each terminal comprising a tubular rivet body made of an electrically conductive material, so as to be an electrical connector, said tubular rivet body comprising first and second tubular parts and an integral collar therebetween, the second part extending through an opening in the resistance element and having its distal portion compacted to form a flange, the resistance element being held between the flange and the collar.

2. A connecting device according to claim 1, wherein:
- the resistance element has a meshed structure comprising a single electrical wire, said wire being coated with an electrically insulating film, and - said terminals, each riveted through a mesh of said resistance element are, together with said resistance element, partly embedded in said device body, each terminal comprising rupture means for tearing said electrical insulating film of the wire, thus ensuring an electrical contact therewith.

3. A connecting device according to claim 2, wherein said rupture means of each connection terminal are disposed between said flanged part and said collar, and extend around said mesh through which the corresponding connection terminal is engaged.

said mesh through which the corresponding connection terminal is engaged.

4. A connecting device according to claim 2, wherein each connection terminal is equipped with at least two electrically conducting washers having an external cross-section greater than that of the meshes of the resistance element, said washers being arranged on either side of the resistance element, respectively, at least one of said washers having tearing asperities thereon for tearing said electrically insulating wire film, thus ensuring the electrical contact with said wire.

5. A connecting device according to claim 1, wherein said device body is overmoulded onto said tubular rivet body, said hollow shaft of the rivet body emerging outwardly on the outer surface of said device body, through an opened cavity thereof, said opened cavity having a cross-section greater than that of said hollow shaft which defines an electrical connection pin.

6. A connecting device according to claim 1, wherein said device body is overmoulded onto each tubular rivet body of said connection terminals and onto said resistance element.

7. A connecting device according to claim 1, wherein said device body is an electro-weldable sleeve having an orifice therethrough, around which said resistance element is disposed, for receiving said pipes to be connected, coaxially therein.

8. A connecting device according to claim 1, defining an electro-weldable branch connector for a transversal connection of said pipes therebetween, said device body having a substantially cylindrical internal surface around which said resistance element is arranged and transversely to

9. A method of manufacturing a connecting device for connecting two pipes therebetween, said pipes being at least partly made of a heat-weldable thermoplastic material, said device comprising a body made of a heat-weldable thermoplastic material having a resistance element for heating said thermoplastic material of the body, to weld the thermoplastic material of the pipes and connection terminals, each connection terminal having a tubular rivet body comprising first and second tubular parts and an integral collar therebetween, said method comprising the steps of:
- riveting each of the connection terminals to the resistance element so that the second tubular part of each connection terminal extends through an opening in the resistance element and has its distal portion compacted to form a flange, the resistance element being held between the flange and the collar; and -over-molding the body of the connecting device onto said connection terminals so that the first tubular part of each connection terminal emerges into an opened cavity of said device body, said cavity opening on an external surface of the device body.

10. A method according to claim 9, in which, prior to the riveting step, each connection terminal further comprises a stud having a head portion and a shank portion connected by a frangible portion, said shank portion extending co-axially through the first and second tubular portions with the head portion abutting the end of the second tubular part, wherein -said riveting step includes the step, following insertion of the second tubular portion through the resistance element, of exerting an axial traction force upon the shank portion of the stud, so that the head portion compacts the distal portion of the second tubular part of the body to form the flange and then the frangible portion breaks so that the body to form the flange and then the frangible portion breaks so that the head portion and the shank portion of the stud are ejected from the body of the connection terminal.