Press-fit contact

A press-fit contact for a plug-in connector, a conductor bar or the like, has a press-in pin at its rear end. A slot is provided in lengthwise direction of the press-in pin. At least one projection is disposed on at least one boundary face of the slot, and a recess, neighboring the projection, is disposed in the circumferential direction of the press-in pin. The recess forms together with the projection a spring element that provides at least part of the retention pressure in the pressed-in condition of the press-in pin.

PRIOR ART

The present invention relates to a press-fit contact for a plug-in connector, a conductor bar or the like, according to the preamble of the independent Claim.

Plug-in connection for printed-wiring boards are offered by Applicant in a variety of different designs. A plug-in connection for printed-wiring boards comprises two plug-in connector elements that can be brought into engagement one with the other. A plug-in connector element generally comprises a plurality of electrically conductive contacts arranged in a plastic housing. A first plug-in connector element is arranged on the printed-wiring board. For connecting the printed-wiring board with other wiring components the second plug-in connector element is fitted on the first plug-in connector element. A plug-in connection of that kind, which comprises a plurality of plug-in contacts arranged in two rows that are implemented as pin contacts and slot contacts, has been known for example from DE 101 19 695 A1. The plug-in connector element arranged on the printed-wiring board is implemented as SMD component where the plug-in connectors are soldered to the surface of the printed-wiring board.

According to a different solution, the plug-in contacts are guided through bores in the card and are soldered to the bottom of the card. As an alternative to the soldering solution the rear end of the plug-in contact may be implemented as press-in pin that is pressed into a bore in the card or a conductor bar by application of pressure. Such a press-fit contact is suited especially for establishing high-current connections.

DE 10 2004 028 202 A1 describes a press-fit contact with a press-in pin provided in its rear portion, which pin is subdivided into two legs, related to the lengthwise direction of the press-fit contact, that are expanded so as to form a slot between the two legs. By expanding the legs in this way, a spring element is produced that provides the necessary retention pressure in the fitted condition of the element.

Now, it is the object of the present invention to provide a press-fit contact for a plug-in connector, a conductor bar or the like, that provides high retention pressure.

DISCLOSURE OF THE INVENTION

In the press-fit contact according to the invention for a plug-in connector, a conductor bar or the like, having a press-in pin at its rear end, there are provided, in lengthwise direction of the press-in pin, a slot, at least one projection disposed on the boundary face of the slot, and a recess neighboring the projection disposed in the circumferential direction of the press-in pin.

The projection, in combination with the recess, provides an elastic element or spring element, which in the pressed-in condition of the contact pin provides an additional high contact pressure or retention pressure.

The resilient effect results from the fact that in the pressed-in condition of the contact pin the projection can resiliently engage into the neighboring recess. The press-fit contact according to the invention therefore permits a strong connection of the press-in pin with the corresponding recess or bore both in mechanical and in electrical respects.

Advantageous further developments and embodiments of the press-fit contact according to the invention are apparent from the attached claims.

One advantageous embodiment provides that at least one projection is provided on both boundary faces of the slot, with a recess provided adjacent the projection, and that the projections face each other at the slot. In the case of that embodiment, the two oppositely arranged projections are pressed one toward the other so that the projections, in combination with the associated recesses, form elastic elements. Thus, an additional increase of the retention pressure in a bore or, generally, in a receiving opening for the press-in pin can be achieved.

According to one embodiment, the recess is configured as an elongated hole in the lengthwise direction of the press-in pin. A suitable projection, which preferably extends in lengthwise direction up to a length maximally equal to the length of the elongated hole, in combination with the recess, makes it possible to selectively influence the properties of the elastic element so obtained and to influence the retention pressure in the pressed-in condition of the press-fit contact.

According to one further development, at least one wedge is arranged on the outer surface of the press-in pin in lengthwise direction. The wedge provides a defined press-in area in the bore for the press-in pin and leads to a desirable non-uniform surface pressure.

An especially advantageous further development of the press-fit contact according to the invention provides that a supporting edge is disposed preferably in the forward area of the press-fit contact. The supporting edge provides a supporting surface that can be used especially for pressing in the press-fit contact according to the invention.

According to another further development, an expanded section of the cross-section is provided in the area of the contact body, which on the one hand improves the stability of the press-fit contact and, on the other hand, reduces the ohmic resistance. It is of particular advantage if the supporting edge is formed simultaneously with the expansion of the cross-section.

According to another further development, at least one key is arranged in the area of the contact body. During assembly of the press-fit contact10in a plug housing, the key engages a corresponding guide provided in the plug housing, thereby fixing the press-fit contact according to the invention at least against undesirable rotation.

According to an especially advantageous embodiment, the press-fit contact according to the invention is produced from a punching.

The punching may be worked in plane condition, for example by milling. Especially, the at least one projection, the at least one recess, the at least one wedge, the expansion of the cross-section, maybe in combination with the supporting edge, and the at least one key can be formed in a simple way in the punching by milling.

The at least one projection may be formed by removing material from the punching on the at least one side of the slot, which later is to become a boundary face, in an area adjacent to the projection to be formed later, in lengthwise direction.

Especially, a plurality of press-fit contacts may be formed from a large punching in a single operation. After completion of the punching, the press-fit contact is given a circular shape by rolling.

Other advantageous further developments and embodiments of the press-fit contact according to the invention will become apparent from the specification. Certain embodiments of the press-fit contact according to the invention are illustrated in the drawing and will be described hereafter in more detail.

FIG. 1shows a perspective overall view of the press-fit contact10according to the invention. The press-fit contact10comprises, related to its lengthwise direction11, a press-in pin12on its rearward end, a contact body13in its central area and contact springs14a-14don its forward end.

At least one key is arranged on the outer surface20of the contact body13. In the illustrated embodiment, four keys21a-21dare arranged on the outer surface20, at the rear end of the contact body13, of which three keys21a,21c,21dare visible in the drawing. Further, four additional keys22a-22dare provided on the outer surface20, at the forward end of the contact body13, of which three keys22a,22c,22dare visible in the drawing. The at least one key21a-21d;22a-22dserves for fixing the press-fit contact10at least against rotation in a plug housing that will be described hereafter.

The press-fit contact10comprises a supporting edge23which in the illustrated embodiment is formed from the forward end of the contact body13. The supporting edge23provides an operative surface for an abutment for the supporting edge, to be described further below, by which the press-fit contact10is pressed into the receiving opening, for example a bore in a printed-wiring board not shown, a conductor bar or the like.

FIG. 2shows a perspective view of a press-in pin12of the press-fit contact10. The press-in pin12comprises a slot30, extending in the lengthwise direction11. At the slot30, first and second boundary faces31a,31bare disposed one opposite the other.

Provided on at least one boundary face31a,31bis at least one projection32a,33a, with a recess35a,36aprovided adjacent to such projection in the circumferential direction34of the press-in pin12. The at least one projection32a,33aforms together with the adjacent projection35a,36aan elastic element or a spring element whereby the projection32a,33acan resiliently engage the neighboring recess35a,36ain the pressed-in condition of the press-in pin12, so that the press-in pin12is capable of providing a high retention pressure in its pressed-in condition. The recess35a,36amay also be described as a cut-out.

In the illustrated embodiment, the recess35a,36ais configured as an oblong hole extending in the lengthwise direction11of the press-fit contact10. The oblong hole has the shape of a needle eye which can be engaged resiliently by the projection32a,33a.

In the illustrated embodiment, two projections32a,33awith adjacent recesses35a,36aare provided in the lengthwise direction11of the press-in pin12. The number of projections32a,33amay vary depending on the length of the press-in pin12. It is thus possible to influence the retention pressure in the pressed-in condition of the press-in pin12.

Another way of influencing the retention pressure consists in varying the length of the projection32a,33ain lengthwise direction11of the contact pin12, in which case the length of the respective adjacent recess35a,36ahas to be adapted to the length of the projection32a,33a. Preferably, the length of the projection32a,33ais selected to be smaller than or maximally equal to the length of the recess35a,36ain order to permit the projection32a,33ato resiliently engage the recess35a,36awithout any problem.

In the illustrated embodiment, at least one projection32a,33a, is provided not only on the first boundary face31a. In the illustrated embodiment, at least one projection32a,32b;33a,33bis provided on both boundary faces31a,31b, each adjoining a neighboring recess35a,35b,36a,36b.The projections32a,32b;33a,33bface each other at the slot30, in the circumferential direction. By disposing projections32a,32b,33a,33bon both sides, at least two elastic elements are provided where projections32a,32b;33a,33bcan resiliently engage neighboring recesses35a,35b;36a,36b. This likewise permits the retention pressure of the press-in pin12to be influenced in its pressed-in condition.

According to one embodiment, at least one key is arranged on the outer surface40of the press-in pin12in the lengthwise direction11. In the illustrated embodiment, two keys41a,41bare provided. The at least one key41a,41bleads to a non-uniform surface pressure in the pressed-in condition of the press-in pin12, which in this case is produced intentionally in order to increase the local pressure.

In principle, the press-fit contact10according to the invention may also be formed by turning. According to an especially advantageous embodiment it is, however, provided to produce the press-fit contact10according to the invention from a punching50, which is illustrated inFIG. 3. The punching50may be worked in plane condition, for example by milling. An essential advantage is derived from the fact that a plurality of press-fit plug-in contacts10can be prepared in a single operation. In the case of the embodiment of the punching50illustrated inFIG. 3, a single punching50has already been separated from a large punching comprising a plurality of prepared press-fit plug-in contacts10. Those parts inFIG. 3that conform with the parts illustrated in the previous Figures are marked by the same reference numerals.

The press-fit contact10is produced from the punching50illustrated inFIG. 3by milling. As part of the operations that can be performed on the punching50in plane condition, the at least one projection32a,32b;33a,33bprovided on the part that later is to become the press-in pin12, can be worked by removing material from the punching outside the projection32a,32b;33a,33b.

Especially, the supporting edge23can be formed particularly easily by milling. The embodiment of the punching50illustrated inFIG. 3shows an expanded section of the cross-section of the contact body13, which may be provided in certain cases. The expanded section of the cross-section improves the stability of the press-fit contact10according to the invention. The expanded section of the cross-section leads to a low ohmic resistance, especially with respect to the preferred embodiment of the press-fit contact10according to the invention, for establishing a high-current connection.

It has been assumed in the case of the illustrated embodiment that the forward end of the expanded section of the cross-section, viewed in lengthwise direction11, is identical to the supporting edge23so that both the expanded section of the cross-section and the supporting edge23can be produced in a single operation, for example by milling.

FIG. 4shows the press-fit contact10according to the invention after arrangement in a plug housing60. During introduction of the press-fit plug-in contact13, the keys22a-22dinitially engage the forward end of the contact body13, whereafter the keys21a-21darranged on the rear end of the contact body13engage guiding recesses61a,61bcorresponding to the keys21a-21d;22a-22dprovided in the plug housing60.

A press-fit contact10is introduced into the plug housing60until the supporting edge23reaches an abutment62for the supporting edge formed in the plug housing60. Pressing-in of the preferably multiple press-fit contacts10arranged in the contact housing60may be effected in the illustrated embodiment by exerting a pressure on the plug housing60from the top, the supporting edge23providing a comparatively large supporting surface, corresponding to the supporting edge, for engagement by an abutment62for the supporting edge23.