EP0341454B1 - Contact pin for testing circuit boards - Google Patents

Contact pin for testing circuit boards Download PDF

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Publication number
EP0341454B1
EP0341454B1 EP89106910A EP89106910A EP0341454B1 EP 0341454 B1 EP0341454 B1 EP 0341454B1 EP 89106910 A EP89106910 A EP 89106910A EP 89106910 A EP89106910 A EP 89106910A EP 0341454 B1 EP0341454 B1 EP 0341454B1
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EP
European Patent Office
Prior art keywords
contact
contact pin
contact head
tip
head
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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EP89106910A
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German (de)
French (fr)
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EP0341454A2 (en
EP0341454A3 (en
Inventor
Daniel Dr.-Ing. Bethge
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Wincor Nixdorf International GmbH
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Wincor Nixdorf International GmbH
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Publication of EP0341454A2 publication Critical patent/EP0341454A2/en
Publication of EP0341454A3 publication Critical patent/EP0341454A3/en
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Publication of EP0341454B1 publication Critical patent/EP0341454B1/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
    • H01R11/00—Individual connecting elements providing two or more spaced connecting locations for conductive members which are, or may be, thereby interconnected, e.g. end pieces for wires or cables supported by the wire or cable and having means for facilitating electrical connection to some other wire, terminal, or conductive member, blocks of binding posts
    • H01R11/11—End pieces or tapping pieces for wires, supported by the wire and for facilitating electrical connection to some other wire, terminal or conductive member
    • H01R11/18—End pieces terminating in a probe

Definitions

  • the invention relates to a contact pin of the type mentioned in the preamble of the claim.
  • Such contact pins are used, for example, for the creation of so-called test adapters. These consist of a plate that is equipped with numerous contact pins; the circuit board to be tested is placed in precise alignment on the test adapter, the contact pins coming into contact with certain test points on the underside of the circuit board. The contact pins are in turn connected to a test circuit. In order to ensure a largely identical pressure of all contact pins on the assigned test points, the contact pins are generally resiliently mounted in sleeves, which in turn are inserted into the plate of the test adapter. The contact pressure is determined by the design of the springs and the contact pins the compression of these springs determines.
  • the test points of the printed circuit board can be formed, for example, by soldering eyes, plated-through holes or also pins of electronic components protruding beyond the underside of the printed circuit board.
  • soldering eyes In order to do justice to the different designs of the soldering points, numerous different contact head shapes have been developed (brochure from INGUN-System, in particular pages 4 to 7).
  • tapered contact heads with different angles are provided for contacting soldering eyes (e.g. Form 01, Form 15, Form 31).
  • Contact heads with a relatively small cone angle must be used so that flux medium residues, oxide layers or other residues on the soldering eye can be safely penetrated and a perfect contact is made.
  • the slender tips thus formed are very susceptible to wear, so that the number of test procedures with such contact pins is limited.
  • the contact heads may have to be made of expensive, high-strength material.
  • Another way to reduce the wear of the cone tip is to make it less slim.
  • this requires a higher pressure force for the contact pin, which generally also requires stronger contact pins and larger sleeves and pressure springs.
  • Special contact heads e.g. Form 07, Form 17
  • These contact heads are triangular or hexagonal so that existing oxide or contamination layers are reliably penetrated at the leading edges of the plated-through holes formed (CH-A-589947) so that they have several sharp cutting edges.
  • Such contact heads are very complex and expensive to manufacture.
  • it must be regarded as a disadvantage that different contact pins have to be used for the two frequently occurring configurations of the contact points, namely soldering eyes or through-bores, which considerably increases the effort, for example, in warehousing or equipping the test adapter.
  • the basic shape of the contact head is tapered; In its simplest and cheapest version, it is circular-conical. In the area of the contact head tip, it is provided with a ground plane parallel to the contact pin axis and running through the contact head tip. This creates a wedge-shaped cutting edge in the area of the tip. It has been shown that with a contact head designed in this way, a foreign layer covering a soldering eye is penetrated much more easily than with conventional contact heads. It is therefore possible, compared to known contact heads intended for the same task, to have obtuse tip angles and lower pressing forces to use. This also results in a reduction in wear. But even if the outermost tip of the contact head already shows wear, the cutting edges emanating from this tip still remain effective, so that the service life of a contact pin designed according to the invention is considerably longer than that of conventional, known contact pins.
  • the cutting edges delimiting the ground plane also allow the contact pin according to the invention to be used in so-called via bores, since these cutting edges can cut through an oxide or contamination layer which may be present on the leading edge of the via bore.
  • the contact pin according to the invention is therefore suitable for the two very frequently occurring contacting tasks, namely the contacting of soldering eyes and of plated-through holes.
  • the circular cone has a tip angle of between 50 ° and 70 °, preferably about 60 °. As already described further above, such a relatively obtuse tip angle is less prone to wear, so that a long service life for the contact pin is ensured.
  • Essentially funnel-shaped contact heads are used for contacting component legs, wire-wrap posts or the like, which catch the component legs even with certain lateral deviations and center them at the bottom of the funnel (INGUN system brochure, form 03, form 04) .
  • the invention is in a further embodiment It is provided that at the foot of the convergingly tapered contact head a groove is formed that extends over the entire circumference of the foot and is open towards the tip of the contact head. If the contact pin according to the invention comes into contact with a component leg or the like, this will generally slide off on the convergingly tapered surface of the contact head until it is caught by the groove.
  • the contact head according to the invention manages with a lower pressure force, it can be made slimmer overall, so that the grid density on the test adapter can be increased when using the contact pins according to the invention.
  • the contact pin 2 shown in Figure 1 consists of a shaft 4 and a contact head 6 formed at the free end of the shaft 4.
  • the contact head 6 is essentially designed as a circular cone 8.
  • the apex angle ⁇ of the circular cone 8 is approximately 60 °.
  • the circular cone 8 is provided in the region of the contact head tip 12 with a ground plane 14 running parallel to the contact pin axis 10 and running through the contact head tip 12.
  • a channel 18 is formed which extends over the entire circumference of the foot and is open towards the contact head tip 12. This serves to catch and pick up component feet sliding on the contact head 6 in order to also make it possible to contact such component feet, as will be explained further below.
  • FIG. 2 shows a plan view of the tip of the contact head 6 and in particular also shows the grinding surface 14 and the groove 18 running around the entire circumference of the foot of the contact head 6.
  • FIG. 3 shows an enlarged representation of the contact head 6 according to FIGS. 1 and 2 in contact engagement with a pad 20.
  • the pad 20 consists in a known manner of the actual solder layer 22 and an impurity layer 24 covering it. This can be caused by flux residues, an oxidation layer or others Impurities are formed.
  • the contaminant layer 24 may be unsuitable Contact pin heads are often not or only insufficiently penetrated, so that no or only insufficient contact is made.
  • the contact head 6 according to the invention forms a relatively blunt wedge with a wedge angle of 60 ° (corresponding to the apex angle of the circular cone 8) in the plane of this grinding surface in the plane of this grinding surface, which is hemmed laterally by the boundary edges of the grinding surface 14 which act as cutting edges.
  • FIG. 4 again shows the contact head 6 with the channel 18 provided in the foot area 16 and extending over the entire circumference of the foot.
  • component feet 26 When contacting component feet 26, they slide along the surface of the circular cone 8 until they are caught and held by the channel 18, as is the case Figure 4 shows.
  • the component feet 26 and / or the contact pin 2 are each slightly deflected laterally in the elastic region, as FIG. 4 also shows.
  • the contact head 6 When contacting via bores, the contact head 6 is centered in the bore, the cutting edges delimiting the ground plane 14 cutting into the input edge of the via bore and possibly penetrating impurity layers present on this input edge.
  • this can be provided with a noble metal coating in a known manner.

Landscapes

  • Measuring Leads Or Probes (AREA)

Description

Die Erfindung betrifft einen Kontaktstift der im Oberbegriff des Anspruches genannten Art.The invention relates to a contact pin of the type mentioned in the preamble of the claim.

Derartige Kontaktstifte werden beispielsweise für die Erstellung von sogenannten Prüfadaptern verwendet. Diese bestehen aus einer Platte, die mit zahlreichen Kontaktstiften bestückt ist; die zu prüfende Leiterplatte wird in genauer Ausrichtung auf den Prüfadapter aufgesetzt, wobei die Kontaktstifte mit bestimmten Prüfpunkten an der Unterseite der Leiterplatte in Kontakt kommen. Die Kontaktstifte sind ihrerseits mit einer Prüfschaltung verbunden. Um einen weitgehend gleichen Andruck aller Kontaktstifte an die zugeordneten Prüfpunkte zu gewährleisten, sind die Kontaktstifte im allgemeinen federnd in Hülsen gelagert, die ihrerseits in die Platte des Prüfadapters eingesetzt werden. Die Andruckkraft ist durch die Auslegung der die Kontaktstifte abstützenden Federn und die Zusammendrückung dieser Federn bestimmt.Such contact pins are used, for example, for the creation of so-called test adapters. These consist of a plate that is equipped with numerous contact pins; the circuit board to be tested is placed in precise alignment on the test adapter, the contact pins coming into contact with certain test points on the underside of the circuit board. The contact pins are in turn connected to a test circuit. In order to ensure a largely identical pressure of all contact pins on the assigned test points, the contact pins are generally resiliently mounted in sleeves, which in turn are inserted into the plate of the test adapter. The contact pressure is determined by the design of the springs and the contact pins the compression of these springs determines.

Die Prüfpunkte der Leiterplatte können beispielsweise durch Lötaugen, Durchkontaktierungen oder auch über die Unterseite der Leiterplatte vorstehende Beinchen von elektronischen Bauteilen gebildet sein. Um den unterschiedlichen Ausbildungen der Lötpunkte gerecht zu werden, sind zahlreiche, unterschiedliche Kontaktkopfformen entwickelt worden (Prospekt der Firma INGUN-System, insbesondere Seiten 4 bis 7). Zur Kontaktierung von Lötaugen sind im allgemeinen kegelige Kontaktköpfe mit unterschiedlich spitzen Winkeln vorgesehen (z. B. Form 01, Form 15, Form 31). Damit auf dem Lötauge befindliche Fluxmittelreste, Oxidschichten oder andere Rückstände sicher durchdrungen werden und ein einwandfreier Kontakt hergestellt wird, müssen Kontaktköpfe mit relativ kleinem Kegelwinkel verwendet werden. Die dadurch gebildeten schlanken Spitzen sind jedoch sehr verschleißanfällig, so daß die Anzahl der Prüfvorgänge mit derartigen Kontaktstiften begrenzt ist. Um diesem Nachteil abzuhelfen, müssen die Kontaktköpfe gegebenenfalls aus teuerem, hochfestem Material hergestellt werden. Eine andere Möglichkeit, den Verschleiß der Kegelspitze zu vermindern, besteht darin, diese weniger schlank auszuführen. Damit wird jedoch eine höhere Andruckkraft für den Kontaktstift erforderlich, was im allgemeinen auch stärkere Kontaktstifte sowie größere Hülsen und Andruckfedern bedingt.The test points of the printed circuit board can be formed, for example, by soldering eyes, plated-through holes or also pins of electronic components protruding beyond the underside of the printed circuit board. In order to do justice to the different designs of the soldering points, numerous different contact head shapes have been developed (brochure from INGUN-System, in particular pages 4 to 7). In general, tapered contact heads with different angles are provided for contacting soldering eyes (e.g. Form 01, Form 15, Form 31). Contact heads with a relatively small cone angle must be used so that flux medium residues, oxide layers or other residues on the soldering eye can be safely penetrated and a perfect contact is made. However, the slender tips thus formed are very susceptible to wear, so that the number of test procedures with such contact pins is limited. To remedy this disadvantage, the contact heads may have to be made of expensive, high-strength material. Another way to reduce the wear of the cone tip is to make it less slim. However, this requires a higher pressure force for the contact pin, which generally also requires stronger contact pins and larger sleeves and pressure springs.

Zur Prüfung von Durchkontaktierungsbohrungen sind besondere Kontaktköpfe entwickelt worden (z.B. Form 07, Form 17), die sich in den Durchkontaktierungsbohrungen zentrieren sollen. Damit an den Eintrittskanten der Durchkontaktierungsbohrungen vorhandene Oxid- oder Verunreinigungsschichten sicher durchdrungen werden, sind diese Kontaktköpfe dreikantig oder sechskantig ausgebildet (CH-A-589947), so daß sie mehrere scharfe Schneidkanten aufweisen. Derartige Kontaktköpfe sind in der Herstellung sehr aufwendig und teuer. Außerdem muß es als Nachteil angesehen werden, daß für die beiden häufig vorkommenden Ausgestaltungen der Kontaktpunkte, nämlich Lötaugen oder Durchkontaktierungsbohrungen, unterschiedliche Kontaktstifte verwendet werden müssen, was den Aufwand beispielsweise der Lagerhaltung oder der Bestückung des Prüfadapters erheblich erhöht.Special contact heads (e.g. Form 07, Form 17) have been developed to test through holes, which should be centered in the through holes. These contact heads are triangular or hexagonal so that existing oxide or contamination layers are reliably penetrated at the leading edges of the plated-through holes formed (CH-A-589947) so that they have several sharp cutting edges. Such contact heads are very complex and expensive to manufacture. In addition, it must be regarded as a disadvantage that different contact pins have to be used for the two frequently occurring configurations of the contact points, namely soldering eyes or through-bores, which considerably increases the effort, for example, in warehousing or equipping the test adapter.

Es ist Aufgabe der vorliegenden Erfindung, einen Kontaktstift der im Oberbegriff des Anspruches 1 genannten Art zu schaffen, welcher einfach und damit preiswert in der Herstellung ist, welcher weitgehend verschleißunempfindlich ist, welcher sowohl für Lötaugen als auch für Durchkontaktierungen verwendbar ist und welcher eine sichere Kontaktierung bei verhältnismäßig geringer Andruckkraft gewährleistet.It is an object of the present invention to provide a contact pin of the type mentioned in the preamble of claim 1, which is simple and therefore inexpensive to manufacture, which is largely insensitive to wear and tear, which can be used both for soldering eyes and for plated-through holes and which provides reliable contacting guaranteed with relatively low pressure.

Diese Aufgabe ist erfindungsgemäß durch die im Kennzeichen des Anspruches 1 enthaltenen Merkmale gelöst.This object is achieved by the features contained in the characterizing part of claim 1.

Der Kontaktkopf ist in seiner Grundform konvergierend zugespitzt; in seiner einfachsten und preiswertesten Ausführung ist er kreiskegelförmig. Im Bereich der Kontaktkopfspitze ist er mit einer zur Kontaktstiftachse parallelen, durch die Kontaktkopfspitze verlaufenden Anschliffebene versehen. Dadurch wird im Bereich der Spitze eine keilförmige Schneidkante erzeugt. Es hat sich gezeigt, daß mit einem derartig ausgebildeten Kontaktkopf eine ein Lötauge überdeckende Fremdschicht sehr viel leichter durchdrungen wird als mit herkömmlichen Kontaktköpfen. Es ist deshalb möglich, gegenüber bekannten, für die gleiche Aufgabe bestimmten Kontaktköpfen stumpfere Spitzenwinkel und geringere Andruckkräfte zu verwenden. Dadurch ergibt sich gleichzeitig eine Verringerung des Verschleißes. Aber selbst dann, wenn die äußerste Spitze des Kontaktkopfes bereits Verschleiß zeigt, bleiben die von dieser Spitze ausgehenden Schneidkanten immer noch wirksam, so daß die Einsatzdauer eines gemäß der Erfindung ausgebildeten Kontaktstiftes wesentlich höher als die herkömmlicher, bekannter Kontaktstifte ist.The basic shape of the contact head is tapered; In its simplest and cheapest version, it is circular-conical. In the area of the contact head tip, it is provided with a ground plane parallel to the contact pin axis and running through the contact head tip. This creates a wedge-shaped cutting edge in the area of the tip. It has been shown that with a contact head designed in this way, a foreign layer covering a soldering eye is penetrated much more easily than with conventional contact heads. It is therefore possible, compared to known contact heads intended for the same task, to have obtuse tip angles and lower pressing forces to use. This also results in a reduction in wear. But even if the outermost tip of the contact head already shows wear, the cutting edges emanating from this tip still remain effective, so that the service life of a contact pin designed according to the invention is considerably longer than that of conventional, known contact pins.

Die die Anschliffebene begrenzenden Schneidkanten ermöglichen außerdem einen Einsatz des erfindungsgemäßen Kontaktstiftes bei sogenannten Durchkontaktierungsbohrungen, da diese Schneidkanten eine eventuell an der Eintrittskante der Durchkontaktierungsbohrung vorhandene Oxid- oder Verunreinigungsschicht durchschneiden können. Der erfindungsgemäße Kontaktstift ist deshalb für die beiden sehr häufig vorkommenden Kontaktierungsaufgaben, nämlich die Kontaktierung von Lötaugen und von Durchkontaktierungen, geeignet.The cutting edges delimiting the ground plane also allow the contact pin according to the invention to be used in so-called via bores, since these cutting edges can cut through an oxide or contamination layer which may be present on the leading edge of the via bore. The contact pin according to the invention is therefore suitable for the two very frequently occurring contacting tasks, namely the contacting of soldering eyes and of plated-through holes.

In bevorzugter Ausgestaltung der Erfindung hat der Kreiskegel einen Spitzenwinkel von zwischen 50° und 70°, vorzugsweise etwa 60°. Wie bereits weiter vorne beschrieben, ist ein derartiger verhältnismäßig stumpfer Spitzenwinkel wenig verschleißanfällig, so daß eine hohe Standzeit für den Kontaktstift sichergestellt ist.In a preferred embodiment of the invention, the circular cone has a tip angle of between 50 ° and 70 °, preferably about 60 °. As already described further above, such a relatively obtuse tip angle is less prone to wear, so that a long service life for the contact pin is ensured.

Für die Kontaktierung von Bauteilbeinchen, wire-wrap-Pfosten oder dergleichen werden im allgemeinen im wesentlichen trichterförmige Kontaktköpfe verwendet, die auch bei bestimmten seitlichen Abweichungen die Bauteilbeinchen einfangen und zum Grund des Trichters zentrieren (INGUN-System-Prospekt, Form 03, Form 04). Um auch die Kontaktierung von Bauteilbeinchen oder dergleichen mit dem erfindungsgemäßen Kontaktstift zu ermöglichen, ist in weiterer Ausgestaltung der Erfindung vorgesehen, daß am Fuß des konvergierend zugespitzten Kontaktkopfes eine über den ganzen Fußumfang verlaufende, zur Kontaktkopfspitze hin offene Rinne ausgebildet ist. Wenn der erfindungsgemäße Kontaktstift mit einem Bauteilbeinchen oder dergleichen in Berührung kommt, wird dieses im allgemeinen an der konvergierend zugespitzten Fläche des Kontaktkopfes abgleiten, bis es von der Rinne gefangen wird.Essentially funnel-shaped contact heads are used for contacting component legs, wire-wrap posts or the like, which catch the component legs even with certain lateral deviations and center them at the bottom of the funnel (INGUN system brochure, form 03, form 04) . In order to enable the contacting of component legs or the like with the contact pin according to the invention, the invention is in a further embodiment It is provided that at the foot of the convergingly tapered contact head a groove is formed that extends over the entire circumference of the foot and is open towards the tip of the contact head. If the contact pin according to the invention comes into contact with a component leg or the like, this will generally slide off on the convergingly tapered surface of the contact head until it is caught by the groove.

Auf diese Weise ist ein Kontaktstift geschaffen worden, welcher im wesentlichen für alle vorkommenden Kontaktierungsaufgaben geeignet ist, so daß die durch unterschiedliche Kontaktstifte verursachte Lagerhaltung sowie der Montageaufwand erheblich verringert werden können.In this way, a contact pin has been created which is essentially suitable for all contacting tasks occurring, so that the storage caused by different contact pins and the assembly effort can be considerably reduced.

Da der erfindungsgemäße Kontaktkopf mit einer geringeren Andruckkraft auskommt, kann er im ganzen schlanker ausgebildet werden, so daß die Rasterdichte auf dem Prüfadapter bei Verwendung der erfindungsgemäßen Kontaktstifte vergrößert werden kann.Since the contact head according to the invention manages with a lower pressure force, it can be made slimmer overall, so that the grid density on the test adapter can be increased when using the contact pins according to the invention.

Ein Ausführungsbeispiel der Erfindung ist in der Zeichnung dargestellt und im folgenden näher beschrieben. Es zeigen:

Figur 1
eine Seitenansicht eines Kontaktstiftes, welcher im Bereich des Kontaktkopfes teilweise geschnitten ist;
Figur 2
eine Draufsicht auf die Spitze des Kontaktstiftes gemäß Figur 1;
Figur 3
in vergrößerter Darstellung eine Seitenansicht eines Kontaktkopfes gemäß Figur 1 im Kontakteingriff mit einem Lötauge;
Figur 4
eine Seitenansicht eines Kontaktstiftes gemäß Figur 3 im Kontakteingriff mit einem Bauteilbeinchen.
An embodiment of the invention is shown in the drawing and described in more detail below. Show it:
Figure 1
a side view of a contact pin, which is partially cut in the region of the contact head;
Figure 2
a plan view of the tip of the contact pin according to Figure 1;
Figure 3
an enlarged side view of a contact head according to Figure 1 in contact engagement with a pad;
Figure 4
a side view of a contact pin according to Figure 3 in contact engagement with a component leg.

Der in Figur 1 dargestellte Kontaktstift 2 besteht aus einem Schaft 4 und einem am freien Ende des Schaftes 4 ausgebildeten Kontaktkopf 6. Der Kontaktkopf 6 ist im wesentlichen als Kreiskegel 8 ausgebildet. Der Spitzenwinkel α des Kreiskegels 8 beträgt etwa 60°.The contact pin 2 shown in Figure 1 consists of a shaft 4 and a contact head 6 formed at the free end of the shaft 4. The contact head 6 is essentially designed as a circular cone 8. The apex angle α of the circular cone 8 is approximately 60 °.

Der Kreiskegel 8 ist im Bereich der Kontaktkopfspitze 12 mit einer zur Kontaktstiftachse 10 parallelen, durch die Kontaktkopfspitze 12 verlaufenden Anschliffebene 14 versehen.The circular cone 8 is provided in the region of the contact head tip 12 with a ground plane 14 running parallel to the contact pin axis 10 and running through the contact head tip 12.

Im Fußbereich 16 des Kontaktkopfes 10 ist eine über den ganzen Fußumfang verlaufende, zur Kontaktkopfspitze 12 hin offene Rinne 18 ausgebildet. Diese dient dazu, am Kontaktkopf 6 abgleitende Bauteilefüßchen zu fangen und aufzunehmen, um auch eine Kontaktierung derartiger Bauteilefüßchen zu ermöglichen, wie weiter unten noch ausgeführt wird.In the foot region 16 of the contact head 10, a channel 18 is formed which extends over the entire circumference of the foot and is open towards the contact head tip 12. This serves to catch and pick up component feet sliding on the contact head 6 in order to also make it possible to contact such component feet, as will be explained further below.

Figur 2 zeigt eine Draufsicht auf die Spitze des Kontaktkopfes 6 und läßt insbesondere auch die Anschlifffläche 14 sowie die um den ganzen Fußumfang des Kontaktkopfes 6 verlaufende Rinne 18 erkennen.FIG. 2 shows a plan view of the tip of the contact head 6 and in particular also shows the grinding surface 14 and the groove 18 running around the entire circumference of the foot of the contact head 6.

Figur 3 zeigt in vergrößerter Darstellung den Kontaktkopf 6 gemäß den Figuren 1 und 2 im Kontakteingriff mit einem Lötauge 20. Das Lötauge 20 besteht in bekannter Weise aus der eigentlichen Lotschicht 22 und einer diese bedeckenden Verunreinigungsschicht 24. Diese kann durch Fluxmittelreste, eine Oxidationsschicht oder andere Verunreinigungen gebildet sein. Die Verunreinigungsschicht 24 kann durch ungeeignete Kontaktstiftköpfe häufig nicht oder nur ungenügend durchdrungen werden, so daß kein oder nur ein ungenügender Kontakt zustandekommt. Der erfindungsgemäße Kontaktkopf 6 bildet durch die angeschliffene Anschlifffläche 14 in der Ebene dieser Anschlifffläche einen verhältnismäßig stumpfen Keil mit einem Keilwinkel von 60° (entsprechend dem Spitzenwinkel des Kreiskegels 8), welcher seitlich durch die als Schneidkanten wirkenden Begrenzungskanten der Anschlifffläche 14 gesäumt ist. In der zur Anschliffebene 14 senkrecht stehenden Ebene, die der Zeichenebene in der Figur 3 entspricht, ergibt sich ein verhältnismäßig spitzer Keil mit einem Keilwinkel, welcher der Hälfte des Spitzenwinkels α entspricht. Diese Konfiguration bewirkt, daß die Kontaktkopfspitze 12 die Verunreingigungsschicht 24 auch bei verhältnismäßig geringem Andruck sicher durchdringt und bis in die Lotschicht 22 eindringt, wie Figur 3 erkennen läßt.FIG. 3 shows an enlarged representation of the contact head 6 according to FIGS. 1 and 2 in contact engagement with a pad 20. The pad 20 consists in a known manner of the actual solder layer 22 and an impurity layer 24 covering it. This can be caused by flux residues, an oxidation layer or others Impurities are formed. The contaminant layer 24 may be unsuitable Contact pin heads are often not or only insufficiently penetrated, so that no or only insufficient contact is made. The contact head 6 according to the invention forms a relatively blunt wedge with a wedge angle of 60 ° (corresponding to the apex angle of the circular cone 8) in the plane of this grinding surface in the plane of this grinding surface, which is hemmed laterally by the boundary edges of the grinding surface 14 which act as cutting edges. In the plane perpendicular to the ground plane 14, which corresponds to the plane of the drawing in FIG. 3, there is a relatively pointed wedge with a wedge angle which corresponds to half the apex angle α. This configuration causes the contact head tip 12 to safely penetrate the impurity layer 24 even with relatively little pressure and to penetrate into the solder layer 22, as can be seen in FIG. 3.

Figur 4 zeigt wiederum den Kontaktkopf 6 mit der im Fußbereich 16 vorgesehenen, über den ganzen Fußumfang verlaufenden Rinne 18. Bei der Kontaktierung von Bauteilefüßchen 26 rutschen diese an der Oberfläche des Kreiskegels 8 entlang, bis sie von der Rinne 18 gefangen und gehalten werden, wie Figur 4 erkennen läßt. Die Bauteilefüßchen 26 und/oder der Kontaktstift 2 werden dabei jeweils geringfügig im elastischen Bereich seitlich ausgelenkt, wie Figur 4 ebenfalls zeigt.FIG. 4 again shows the contact head 6 with the channel 18 provided in the foot area 16 and extending over the entire circumference of the foot. When contacting component feet 26, they slide along the surface of the circular cone 8 until they are caught and held by the channel 18, as is the case Figure 4 shows. The component feet 26 and / or the contact pin 2 are each slightly deflected laterally in the elastic region, as FIG. 4 also shows.

Bei der Kontaktierung von Durchkontaktierungsbohrungen wird der Kontaktkopf 6 in der Bohrung zentriert, wobei die die Anschliffebene 14 begrenzenden Schneidkanten in die Eingangskante der Durchkontaktierungsbohrung einschneiden und eventuell an dieser Eingangskante vorhandene Verunreinigungsschichten durchdringen.When contacting via bores, the contact head 6 is centered in the bore, the cutting edges delimiting the ground plane 14 cutting into the input edge of the via bore and possibly penetrating impurity layers present on this input edge.

Es hat sich gezeigt, daß durch die günstige Ausgestaltung des Kontaktkopfes 6 mit einem Spitzenwinkel von 60° und der im Spitzenbereich 12 vorgesehenen Anschlifffläche 14 die Schubspannung zwischen der Lotschicht 22 und der Verunreinigungsschicht 24 am größten ist, so daß letztere abplatzt. Wegen der besonderen Keilform der Kontaktkopfspitze 12 ist nur eine geringe Andruckkraft (beispielsweise 0,8 N) für eine sichere Kontaktierung erforderlich. Die geringe Andruckkraft wiederum hat zur Folge, daß die Kontaktstifte nicht die Stabilität bisher gebräuchlicher Kontaktstifte benötigen und damit kleiner im Durchmesser gehalten werden können. Dadurch können mehr Kontaktstifte pro Flächeneinheit eingesetzt werden, d.h. auch Leiterplatten mit dicht nebeneinanderliegenden Prüfpunkten können geprüft werden.It has been shown that the favorable design of the contact head 6 with a tip angle of 60 ° and the grinding surface 14 provided in the tip area 12 causes the shear stress between the solder layer 22 and the contamination layer 24 to be greatest, so that the latter flakes off. Because of the special wedge shape of the contact head tip 12, only a small pressing force (for example 0.8 N) is required for reliable contacting. The low pressure force in turn means that the contact pins do not require the stability of previously used contact pins and can therefore be kept smaller in diameter. This allows more contact pins to be used per unit area, i.e. Printed circuit boards with test points close to each other can also be tested.

Um eine Bildung schlecht leitender Oxidschichten auf dem Kontaktkopf 6 zu vermeiden, kann dieser in bekannter Weise mit einem Edelmetallüberzug versehen sein.In order to avoid the formation of poorly conductive oxide layers on the contact head 6, this can be provided with a noble metal coating in a known manner.

Claims (6)

  1. Contact pin for functional testing of printed-circuit boards or the like, having a convergently pointed contact head which is constructed on its free end and is provided with a ground plane (14) extending through the tip (12) of the contact head, characterized in that the ground plane extends parallel to the axis (10) of the contact pin.
  2. Contact pin according to Claim 1, characterized in that the contact head (6) is constructed as a circular cone (8).
  3. Contact pin according to Claim 2, characterized in that the axis of the circular cone (8) coincides with the axis (10) of the contact pin.
  4. Contact pin according to Claim 2 or 3, characterized in that the circular cone (8) has a vertex angle of between 50° and 70°, preferably approximately 60°.
  5. Contact pin according to one of Claims 1 to 4, characterized in that a groove (18) which extends over the entire base circumference and is open towards the tip (12) of the contact head is constructed in the base region (16) of the convergently pointed contact head (6).
  6. Contact pin according to one of Claims 1 to 5, characterized in that it is mounted in a longitudinally displaceable fashion and resiliently supported in a sleeve.
EP89106910A 1988-05-09 1989-04-18 Contact pin for testing circuit boards Expired - Lifetime EP0341454B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE8806162U DE8806162U1 (en) 1988-05-09 1988-05-09
DE8806162U 1988-05-09

Publications (3)

Publication Number Publication Date
EP0341454A2 EP0341454A2 (en) 1989-11-15
EP0341454A3 EP0341454A3 (en) 1990-06-13
EP0341454B1 true EP0341454B1 (en) 1993-12-15

Family

ID=6823887

Family Applications (1)

Application Number Title Priority Date Filing Date
EP89106910A Expired - Lifetime EP0341454B1 (en) 1988-05-09 1989-04-18 Contact pin for testing circuit boards

Country Status (2)

Country Link
EP (1) EP0341454B1 (en)
DE (2) DE8806162U1 (en)

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2292236A (en) * 1941-01-14 1942-08-04 Carl P Martin Prod
DE2030707B2 (en) * 1970-06-22 1971-11-25 Siemens AG, 1000 Berlin u. 8000 München CONTACT DEVICE FOR DETACHABLE ELECTRICAL CONTACT WITH THE CONTACT POINTS OF A CIRCUIT ARRANGEMENT
DE2041280B2 (en) * 1970-08-19 1972-12-21 CONTACT DEVICE FOR DETACHABLE ELECTRICAL CONTACT WITH THE CONTACT POINTS OF A CIRCUIT ARRANGEMENT
CH589947A5 (en) * 1974-02-13 1977-07-29 Ingun Ag Test pin for printed circuit boards - with spring loaded shank in barrel and test end with conical hollow for boards test point
DE2852886A1 (en) * 1978-12-07 1980-06-19 Feinmetall Gmbh Probe contact assembly for printed circuit boards - includes tubular housing with spring-loaded check pin terminating with serrated contact head
FR2479643A1 (en) * 1980-03-26 1981-10-02 Sodeteg Tai PROBE FOR DEVICE FOR TESTING PRINTED CIRCUITS AND TEST DEVICES INCORPORATING SUCH A PROBE
DE3441480A1 (en) * 1984-11-13 1986-05-15 MANIA Elektronik Automatisation Entwicklung und Gerätebau GmbH, 6384 Schmitten CONTACT PEN
DE3500227A1 (en) * 1985-01-05 1986-07-10 Riba-Prüftechnik GmbH, 7801 Schallstadt Probe needle
DE8706546U1 (en) * 1986-05-12 1987-09-17 Feinmetall Gmbh, 7033 Herrenberg, De

Also Published As

Publication number Publication date
EP0341454A2 (en) 1989-11-15
DE8806162U1 (en) 1989-09-07
DE58906395D1 (en) 1994-01-27
EP0341454A3 (en) 1990-06-13

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