EP1594193B1 - Contact arrangement - Google Patents

Abstract

The contact (10) has a pair of arms (12, 13) with outer ends having end faces extending at an acute angle to an insertion direction. The arms are spaced apart transversely of the direction. Inner contact bumps projecting on the arms are spaced apart transverse to the direction by a predetermined inner spacing. Outer bumps projecting on the arms are spaced apart transverse to the direction by a predetermined outer spacing.

Description

The invention relates to an electrical contact device for contacting with mating contacts such as printed conductors of a printed circuit board or metallized plastic contour (MID) (MID = Molded Interconnect Devices), contact blades od. Like., Wherein the contact device on the mating contacts associated edges to sliding contacts such as fork spring contacts, Double leg flat springs od. Like. Includes and wherein each contact leg of a contact near its free end a mouth inclined surface and its free end facing away behind at least one to the other contact legs facing contact tip.

With FR 1 392 205 A a fork spring contact is known which has a plurality of contact arms, each with a contact tip. Each contact arm is equipped with a single contact group. The contact arms are arranged to each other such that the contact blades are arranged one behind the other in a plugging direction. Each contact group is individually spring-mounted.

In US 3,858,957 a contacting device is disclosed which uses double-leaf flat springs. Each spring leg has in the insertion direction two successively arranged contact blades. An associated circuit board is provided with a Spreiznocken. When running the front contact points on the expansion cams double-leaf flat springs are spread so that the downstream contact points are arranged contactless above and below. When the front contact points leave the area of the expansion cam, occasionally the trailing contact points on the tracks of the circuit board. The aim of this contacting is It is to realize a secure contact with low insertion forces.

Contact devices of this type are disclosed in the prior art in further variants. An example shows the DE 30 23 614 C2 , which has a connector strip for liquid crystal displays to the content. This document addresses the problem of achieving the smoothest possible insertion of the liquid crystal display into the connector strip. The aim is to achieve a reliable contact pressure as well as the ability to easily capture hard edges of the liquid crystal display. As a previous disadvantage is stated that the edge of the liquid crystal display as much as possible bevelled ("broken") had to be. As a problem solution suggests DE 30 23 614 C2 To form the legs of the fork springs so asymmetrical that the liquid crystal display is initially introduced obliquely to the opening of the fork springs without overcoming a spring force and then by tilting to the parallel of the longitudinal axis of the fork springs widens both legs for double-sided contacting in the connector strip.

As reliable as this problem solution may be, so is the tilting of the to be connected with the contact device Object, so here the liquid crystal display, not desirable in all applications. If, for example, one thinks of highly miniaturized plug-in devices for mobile telephones or the like, such handling is practically unreasonable for the user.

In connection with contact devices of the type mentioned, there is also the problem that the finishing layers of the fork spring contact, with which they are coated, can be easily damaged by plugging operations. Usually, the contact tips are formed on the punched edges of the fork spring contacts and tinned or even gold plated to ensure excellent electrical contact. When contacting sharp-edged PCB edges or incompletely deburred blade contacts, these thin finishing layers may be damaged with the consequence that the contact resistances are adversely affected and the long-term stability of the contacts is impaired.

Object of the present invention is essentially to provide a contact device of the presupposed as known type, which is simple and particularly protected against damage to their contact surfaces.

The invention solves this problem with the features of claim 1 and is accordingly characterized in that the respective muzzle inclined surface merges into an additional contact tip, which is upstream of the contact tip in the insertion direction of the contact as a leading contact tip.

The essential core of the invention is thus to provide additional contact tips that eliminate the potentially contact-damaging influence of mating contacts, in particular their sharp or rugged edges or at least "defuse" before the conductive parts of the mating contacts come into operative contact with the actual contact blades.

In contrast to the prior art after said DE 30 23 614 C2 is according to the invention, no pivoting or tilting part of a connector required, so that the contact device according to the invention is ideal for a conventional plug-in device with only straight-line insertion and withdrawal movements.

For the purpose of establishing contact devices with fork-shaped contact elements so that when inserting printed circuits only a small insertion force is required, suggests the DE 1 046 137 Provide two or more adjacent contact elements for each contact unit, wherein the contact-forming tips of the contact elements are arranged offset in the insertion direction such that give the contact elements of each contact in succession upon insertion of the printed circuit. Here, each contact device consists of at least two, preferably three adjacent fork-shaped contact elements, each having a Kontaktkuppenpaar in opposing arrangement. Although "additional contact dome" are also present here, but not upstream in the sense of the invention, the actual contact tip in the insertion direction of the contact leading. This is due to the fact that in the contact device of DE 1 046 137 the cup pairs are arranged side by side. The crests therefore each act - as in conventional fork spring contacts - in only one line. There is no arrangement in which a dome - as in the invention - makes a "preliminary work" for another dome arranged in the same line. In principle, therefore, this prior art is merely a doubling or tripling of a conventional fork spring contact with no effect in view of the problem of the present invention. It is So according to the prior art DE 1 046 137 not possible to solve the problem underlying the invention.

In a further embodiment of the subject invention, it is provided that the muzzle inclined surface in each case encloses a steep angle (W) of about 40 ° to 55 ° to the insertion direction and that the transition from the leading contact tip to the actual contact tip in each case flatter than the mouth inclined surface and each includes an angle (W) of about 15 ° to 30 ° to the direction of insertion. Compared to conventional angles of existing on fork spring contacts muzzle slopes these invention "special" are formed by special steep position to come as close as possible to the goal, annoying burrs, edges od. Like. The mating contact elements to settle.

With regard to constructional simplicity and the target of a, if desired, also highly miniaturized contact device, preferably all the contact tips are integrally formed with the contact, as well as with material uniformity.

Finally, the invention provides an embodiment in which the leading contact tip of a contact leg with respect to the leading contact tip of the other contact leg is offset by a certain amount in the insertion direction. This is particularly advantageous in that the leading contact points are successive, i. in temporal succession, come into effect and thus each uninfluenced by the other leading contact tip can perform their intended function.

The production, in particular so the punching, of a contact element according to the invention differs, apart from only the geometric shape of the generating tool, not from the production of a conventional simple Fork spring contact. Consequently, the invention requires virtually no additional effort and expense.

Fig. 1

eine erfindungsgemäße Kontaktvorrichtung unmittelbar vor dem Aufstecken auf eine Leiterplatte,

Fig. 2

dieselbe Kontaktvorrichtung bei Berührung beider Mündungsschrägflächen durch Stirnkanten der Leiterplatte,

Fig. 3

die Kontaktvorrichtung nach dem Passieren der beiden voreilenden Kontaktkuppen an den Leiterplattenkanten vorbei,

Fig. 4

die Kontaktvorrichtung vor dem Auftreffen einer Kante der Leiterplatte auf eine Kontaktkuppe,

Fig. 5

die Kontaktvorrichtung im bestimmungsgemäßen Kontaktierzustand, in dem beide Kontaktkuppen Leiterbahnen derselben kontaktieren, und

Fig. 6

eine herkömmliche Kontaktvorrichtung entsprechend dem Stand der Technik.

Moreover, the invention will become apparent from the following description of an embodiment with reference to the accompanying drawings. All drawings show in each case the same side view and in considerable magnification, a contact device which is designed as a fork spring contact, in detail:

Fig. 1

a contact device according to the invention immediately before plugging onto a printed circuit board,

Fig. 2

the same contact device when touching both muzzle inclined surfaces by end edges of the printed circuit board,

Fig. 3

the contact device after passing the two leading contact points past the circuit board edges,

Fig. 4

the contact device before hitting an edge of the printed circuit board on a contact tip,

Fig. 5

the contact device in the intended contacting state in which contact both contact pads of the same, and

Fig. 6

a conventional contact device according to the prior art.

Before the invention with reference to the in the Fig. 1 to 5 illustrated embodiment is described below first with reference to Fig. 6 on the general state of the art received.

A total of 10 designated contact device comprises a number of contact springs 11 which are formed as fork springs with fork legs 12 and 13 and a connecting this fork web 14. At the latter, a foot part or conductor connection section 15 is connected in particular material-material-cohesively. This may be a crimp termination for stripped conductor ends, but may also be e.g. around an insulation displacement fork. Moreover, the section 15 is not the subject of the present invention.

Each of the two fork legs 12, 13 has on its side facing the opposite fork legs 13 and 12, a so-called contact tip 16 and 17, respectively. At the in Fig. 6 illustrated embodiment, the two contact caps 16 and 17 are offset in the longitudinal or insertion direction 18 by a designated 19 degree. This serves to facilitate contacting in so far as the contact tip 16 and then only the contact tip 17 a counter contact 20 is applied, which should be in all the illustrated embodiments as an example, a printed circuit board 21 with traces 22, 23. Alternatively, the mating contact 20 can also be a flat plug or blade contact or else a so-called metallized plastic contour. By the offset 19 reduce the insertion forces due to the time offset of the maximum deflection of the fork legs 12 and 13 during a plug-in operation.

The fork spring contact 11 is cut perpendicular to the plane of a flat rectangular contact plate. The contact tips 16 and 17 provide with the punching surfaces their contact surfaces 16a and 17a ready. In particular, these contact surfaces 16a and 17a, possibly also the entire contact spring 11, are in terms of optimal electrical contact enhanced by a galvanic coating such as tinning or gilding. This finishing layer is very sensitive and can be damaged, for example, by sharp edges 24 of mating contacts 20. According to the state of the art Fig. 6 are therefore the marginal edges of a circuit board 20 by training two bevels 31 a little "defused". Nevertheless, they still stay out Fig. 6 apparent, despite the chamfering 31 sharp edges 24 as possibly damaging left over.

Moreover, the contact spring 11 on the inner sides of its two fork legs 12 and 13 still so-called muzzle inclined surfaces 26, 27 as Aufsteckführung and slideways for the smoothest possible contact with the mating contact 20. In addition, the inclined surfaces 26 and 27 effect as a result of their wedge spreading the soft spreading the self-spring tension fork legs 12 and 13th

In addition, the object of the invention will now be described with reference to FIG Fig. 1 to 5 described.

First, in accordance with the state of the art, as in Fig. 6 and the above description has been explained, a contact device 10 has a contact spring 11 with two fork legs 12 and 13, a web 14 connecting them to one another and a conductor connection section 15. Again, two, optionally in the axial direction with not necessary and not shown here offset offset contact caps 16 and 17 are provided with their contact surfaces 16a and 17a.

This contact device 10 or the contact spring 11 is now designed in a special way to be contacted even with sharp edges 24, 25 of mating contacts 20 such as a printed circuit board 21 with conductors 22 and 23, without the contact surfaces 16a, 17a or Their finishing layers suffer damage.

Preceded by the two contact blades 16 and 17, ie located in front in the insertion direction 18, a further, so-called leading contact tip 29 and 30 is provided on each of the two fork legs 12 and 13 respectively. Their inner surfaces are designated 29a and 30a. As well as out Fig. 1 can be seen, the contact blades 29 and 30 and thus also their inner surfaces 29a and 30a on a longitudinal offset, in Fig. 1 denoted by 28. At the leading contact blades 29 and 30 close to the free end of the fork legs 12 and 13 each have a mouth inclined surface 26 and 27 at.

These muzzle inclined surfaces 26 and 27 close to the plugging direction 18 at an angle W, which is significantly greater than the angle w, corresponding to the muzzle inclined surfaces 26 and 27 in the prior art Fig. 6 form and on the order of about 30 °. In the illustrated embodiment, the angle W is about 48 °. Consequently, the inclined surfaces 24 and 25 are inclined much steeper to the direction of insertion 18 in the subject invention and thus act on the edges 24 and 25 of a mating contact 20 very aggressive.

In the following, the effect of the structural design of the contact device 10 will be correspondingly Fig. 1 explained in detail during a plug-in operation, in which the contact device 10 is mated with a mating contact 20.

In Fig. 1 when inserting the contact device 10 in the direction of arrow 18 (plug-in direction) on a circuit board 21 first the muzzle inclined surface 27 on the sharp edge 25 of the circuit board 21. While simultaneously spreading the fork leg 13 with respect Fig. 1 to the right scrapes now the mouth inclined surface 27 along the edge 25 along and breaks them at least in the way easy to remove a sharp burr and / or sharpen the sharp edge.

Corresponding Fig. 2 now has the mouth inclined surface 27 leave the now smoothed edge 25. Meanwhile, the opposite edge 24 of the circuit board 21 has slid along the opposite muzzle inclined surface 26 a piece and has also smoothed this. At the same time the force contact between the edge 24 and the mouth inclined surface 26, the fork spring legs 12 and 13 further spread.

In Fig. 3 On the one hand, it can be seen that the edges 24 and 25 of the printed circuit board 21 have been chamfered and that now the printed circuit board 21 is located between the two mouth inclined surfaces 26 and 27 of the contact device 10.

In the further course of the attachment of the contact device 10 touches the circuit board 21, as in Fig. 4 shown, the circuit board edge 24, the one inclined surface 32 (for clarity in FIG Fig. 3 shown), which is formed between the leading contact tip 29 and the actual contact tip 16 and an inclination of about 15 ° (angle w in Fig. 3 ) having. The contact of the printed circuit board edge 24 with the inclined surface 32 optionally leads to further sizing of its edge 24. On the other hand, the leading contact tip 27 runs on a conductor track 22 of the printed circuit board 21.

Now slides the inclined surface 33, which is present between the leading contact tip 27 and the actual contact tip 17, on the second circuit board edge 25, until finally accordingly Fig. 5 the two actual contact blades 16 and 17 of the fork legs 12 and 13 contact the tracks 22 and 23. These are provided in the embodiment on both sides of the circuit board 21, but the circuit board 21 could also only be provided on one side with a conductor track. Fig. 5 shows the final, operational contact state.

As can be clearly seen from the above, the essence of the invention is to pre-assign the actual contact tips 16 and 17 to the free end of the fork legs 12 and 13 so-called leading contact blades 29 and 30, in particular in cooperation with the previously arranged aggressive muzzle inclined surfaces 26th and 27, the edges 24 and 25 of the mating contact 20, for example a printed circuit board 21, a blade contact or an MID break or finish or chamfer.

If then the actual contact blades 16 and 17 touch the mating contact, it has already lost its aggressiveness and therefore can no longer affect the sensitive contact surfaces 16a and 17a on the contact tips 16 and 17.

As far as the present invention has been described with reference to contacts, which are commonly referred to as fork spring contacts, it should be noted that they can be realized in other contact springs, esp. Double-leg spring contacts such as flat contact springs, in which the spring legs face each other with their rolling surfaces and the crests are created by bending the leaf spring-like legs.

Claims (5)

1. Electric contact device (10) for making contact with counter-contacts (20) such as conductor tracks (22, 23) of a printed circuit board (21) or metallised plastic contour (MID), contact blades or the like, wherein the contact device (10) comprises contacts (11), such as forked-spring contacts, double-leg flat springs or the like, which are to be pushed over marginal edges (24, 25) associated with the counter-contacts (20), and wherein each contact leg (12, 13) of a contact (11) has, close to its free end, an oblique face (26, 27) of the orifice, and also, behind it and facing away from said free end, at least one contact dome (16, 17) that points towards the other contact leg (13, 12),
   characterised in that the individual oblique face (26, 27) of the orifice merges into an additional contact dome (29, 30) which is mounted, as a leading contact dome, in front of the contact dome (16, 17) in the direction of plugging-in (18) of the contact (11).
2. Contact device according to claim 1, characterised in that the oblique face (26, 27) of the orifice forms, in each case, a steep angle (W) of about 40° to 55° in relation to the direction of plugging-in (18).
3. Contact device according to claim 1 or 2, characterised in that the transition from the leading contact dome (29, 30) to the actual contact dome (16, 17) extends in a shallower manner, in each case, than the oblique face (26, 27) of the orifice and forms, in each case, an angle (w) of about 15° to 30° in relation to the direction of plugging-in (18).
4. Contact device according to one of claims 1 to 3, characterised in that all the contact domes (16, 17; 29, 30) are constructed in one piece with, and integrally with/from the same material as, the contact (11).
5. Contact device according to one of claims 1 to 4, characterised in that the leading contact dome (29) belonging to one contact leg (12) is arranged so as to be offset (dimension 28) with respect to the leading contact dome (30) belonging to the other contact leg (13) in the direction of plugging-in (18).

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