Patent Description:
The plug connector normally has an insulated pin housing with a circumferential flange and a chamber, wherein a plurality of contact pins which are plugged into a pin strip are arranged inside the pin housing. In order to guarantee a secure fit of the contact pins in the pin housing, the contact pins have a base body and retaining elements moulded thereon which, for example, take the form of pairs of lugs which project beyond the circumference of the contact pin and which have a rising contour opposite to the mounting direction of the contact pin. Upon insertion/ assembly of the contact pin into the pin strip, said contact pin is successively expanded by the wedge shape of the retaining element, which facilitates the production of the plug connection and delimits the assembly forces. In the event of a straining of the contact pin, for example when producing a plug connection between a male plug connector and a female mating plug connector, the precipitous rear side of the retaining element is interlocked with the surrounding material of the pin strip, whereby a retention force is mobilised. If the retention force is exceeded during the plug-in process, the base material of the pin housing which surrounds the retaining element is placed locally, ruptured or broken up.

In order to increase the maximum retention force, arranging at least two retaining elements in the direction of the longitudinal axis of the contact pin successively is known. It is disadvantageous that the retaining element, which is successive in the longitudinal direction, touches the already pre-damaged base material, whereby this successive retaining element can only provide a reduced contribution to the retention force.

Arranging the retaining elements, which are successive in the longitudinal direction, offset by <NUM>° in the circumferential direction of the base body of the contact pin is further known, such that when the retention force is exceeded, both retaining elements touch undamaged base material, the very high assembly forces proving to be disadvantageous.

The problem of the present invention is thus to provide a contact pin for an electrical plug connector which overcomes the abovementioned disadvantages, enables the highest possible retention forces and furthermore does not require assembly forces which are excessively high during assembly. Furthermore, the contact pin should be able to be produced cost-effectively and efficiently.

<CIT> teaches a connector with a housing formed with press-in holes, and terminals to be pressed into the press-in holes. Each terminal includes a tab connectable with a mating terminal, a base extending from the tab, and two press-in portions arranged side-by-side along the longitudinal direction on the base. Each press-in portion has press-in pieces projecting from the base in opposite outward directions and pressed into the housing.

These problems are solved by a contact pin with the features of Claim <NUM> and by a plug connector with the features of Claim <NUM>. Preferred developments are specified in the dependent claims.

An inventive contact pin for a plug connector comprises a base body with a longitudinal axis x and a surface O. A first end of the contact pin is adapted to be plugged into an opening of a pin strip of the plug connector, the contact pin having at least four retaining elements which are moulded on the base body. Two retaining elements are each arranged successively spaced apart along the longitudinal axis x. Moreover, two further retaining elements are each arranged oppositely at the same point of the longitudinal axis x in the circumferential direction. In this case, the retaining elements arranged successively are arranged offset from one another in the circumferential direction at an angle W1. According to the invention, it is envisaged that the angle W1 is smaller than <NUM>°.

Such an arrangement of the retaining elements on the base body ensures that each retaining element, in the case of an undesired, touches at least partially undamaged base material of the pin strip and thus all retaining elements provide an approximately equal contribution to the retention force. The retention force thus becomes approximately constant along a large part of the withdrawal path.

At the same time, by means of the arrangement of the angle W1 and by means of its relatively small extension along the circumference of the contact pin, a delimitation of the assembly force which is to be applied for the assembly of the pin strip and a good guidance of the contact pin during the plug-in process are ensured. In this case, it is advantageous that the angle W1 is smaller than <NUM>°, preferably smaller than <NUM>°, particularly preferably smaller than <NUM>°.

In principle, it is possible according to the invention that the retaining elements are formed by accumulations of material which protrude from the base body and which can be produced by various means. It is conceivable that these accumulations of material are provided by local deforming of the contact pin or by applying additional material by means of welding, soldering or adhesion.

In a particularly preferable configuration, the contact pin has at least eight retaining elements, four of the retaining elements each being arranged relative to the longitudinal axis x on the same cross-section Q, those four retaining elements which are at a shorter distance relative to the first end than the remaining four retaining elements forming a first group and the remaining retaining elements a second group.

A first pair and a second pair of the four retaining elements of the first group preferably each have a first distance a from one another, the first distance a being the same size in the case of the first pair and the second pair. Furthermore, a third pair and a fourth pair of the four retaining elements of the second group each have a second distance a' from one another, the second distance a' being the same size in the case of the third pair and the fourth pair.

In a preferred configuration, the first distance a is greater than the second distance a', the first pair and the third pair as well as the second pair and the fourth pair being arranged such that, in the event that the positions of all the retaining elements are projected onto the y-z plane, the projections of the third pair are located centrally between the projections of the first pair, and the projections of the fourth pair are located centrally between the projections of the second pair. In this manner, it is possible that, upon insertion of the contact pin into the opening of the pin strip, this is successively expanded in adjacent regions, which leads to the required assembly force being delimited. At the same time, each retaining element touches new base material without pre-damaging or with only a limited amount of pre-damage by preceding retaining elements, whereby the desired uniformly high deployment of the retention force is achieved.

This effect can advantageously be amplified by at least two retaining elements, which are not arranged on the same cross-section Q relative to the longitudinal axis x, protruding to varying degrees from the base body, preferably the one of the two retaining elements which is moulded on the base body further away from the first end than the other retaining element protruding further from the base body.

In a preferred embodiment, the retaining elements are moulded on the base body by a forging method, stamping method or embossing method.

Advantageously, the retaining elements are moulded on the base body in a wedge-shaped or wing-shaped manner such that they increasingly protrude from the base body at an increasing distance from the first end.

According to the invention, the retaining elements are formed, with respect to their number and their dimensions, such that the retention force of the contact pin from the pin housing reaches a value greater than or equal to <NUM> N, preferably greater than or equal to <NUM> N, particularly preferably greater than or equal to <NUM> N.

A further subject-matter of the invention forms a plug connector for producing a mechanical and electrical connection to a mating plug, the plug connector having a pin housing with a pin strip for receiving at least one contact pin according to the invention.

Further features, possible applications and advantages of the invention can be gathered from the following description of the exemplary embodiments of the invention, which are depicted in the figures. It should be noted here that the features depicted are merely descriptive in character and can also be used in combination with features of other further developments described above, and they are not intended to limit the invention in any way.

The invention is explained in more detail hereafter with reference to the appended figures, wherein the same reference numbers are used for the same features. In the drawings:.

<FIG> shows a contact pin <NUM> already disclosed in the prior art for a plug connection. The contact pin <NUM> consists of a mechanically resistant and electrically conductive material. A first end <NUM> of the contact pin <NUM> is provided to be plugged into an opening of a pin strip of a pin housing of a male plug connector.

The contact pin <NUM> has a plurality of retaining elements <NUM> moulded on a base body <NUM> so that a pin strip which is assembled in this way is mechanically resilient when producing a plug connection between a male plug connector and a female mating plug. As can be inferred from <FIG>, these retaining elements <NUM> are in this case arranged successively in the direction of a longitudinal axis x of the contact pin <NUM>, which is known from the prior art and is not according to the invention because this configuration has the known disadvantages with regard to the amount of a retention force which can be mobilised to a maximum extent.

<FIG> schematically shows a cross-section Q and an inventive arrangement of the retaining elements <NUM> on the base body <NUM> of the contact pin <NUM>. This cross-section Q, which can have any shape in lieu of the depicted rectangular shape, for example round or square, is perpendicular to the longitudinal axis x shown in <FIG>, which defines a first axis of a spatial, Cartesian coordinate system. In principle, the retaining elements <NUM> can be moulded on the base body <NUM> in a wedge-shaped or wing-shaped manner by a forging method, stamping method or embossing method such that they increasingly protrude from the base body <NUM> at an increasing distance from the first end (not depicted in detail).

<FIG> further shows a second axis y and a third axis z. The y-z plane which is spanned by these two axes is the plane in which the cross-section of the contact pin <NUM> can be specified at each point of the longitudinal axis x by corresponding y-z coordinates. An origin U of the coordinate system is specified in <FIG> as the intersection of the two coordinate axes, the longitudinal axis x consequently runs perpendicular to the plane of projection, also through this point. The cross-section Q is delimited by a surface O of the base body <NUM>.

The contact pin <NUM> depicted in the figures has a first end which is adapted to be plugged into an opening of the pin strip of the plug connector. In principle, it is envisaged that the contact pin <NUM> has at least four, in the depicted exemplary embodiment eight, retaining elements <NUM> moulded on the base body <NUM>. Two retaining elements <NUM> are each arranged successively spaced apart along the longitudinal axis x, and two retaining elements <NUM> are each arranged oppositely at the same point of the longitudinal axis x in the circumferential direction. The retaining elements <NUM> arranged successively are arranged offset from one another in the circumferential direction at an angle W1 in such a way that the angle W1 is smaller than <NUM>°.

It is an advantage if the angle W1 between the successively arranged retaining elements <NUM> is so small that a delimitation of the assembly force which is to be applied for the assembly of the pin strip with a contact pin <NUM> is ensured.

In principle, such an arrangement and configuration of the retaining elements <NUM> guarantees the prevention of the contact pin <NUM> being pushed out of the pin strip in the assembled state. This can be seen in <FIG>, for example, and is later discussed in detail.

A position of each retaining element <NUM> on the base body <NUM> is given in the coordinate system in <FIG> by a coordinate triple (xH, yH, zH) based on a centroid of volume <NUM> of each retaining element <NUM>. The shape of the retaining elements <NUM> in the illustration is purely schematic and only serves to show the arrangement thereof along the surface of the base body <NUM>.

When viewing <FIG>, the positions of all the retaining elements <NUM> are projected onto the y-z plane as a common plane, in order to be able to describe their arrangement in a clear manner. The arrangement of the retaining elements <NUM> on the surface O is described hereinafter.

Four retaining elements <NUM> each have positions which differ in terms of value xH and are arranged on the same cross-section Q relative to the longitudinal axis x; this can be understood, for example, with reference to <FIG>, which in the left part shows a lateral view and in the right part a plan view of the inventive contact pin <NUM> rotated by <NUM>° relative thereto.

Two retaining elements <NUM>, which are amalgamated in a first pair <NUM> and which have a distance a from one another, can be seen in the right part. A second pair <NUM>, which is not identifiable as such in <FIG> and which is arranged symmetrical with respect to the first pair relative to the longitudinal axis x, is located on the opposite side of the contact pin <NUM> which is not depicted. This can be easily understood taking into account the left part of <FIG> and with reference to <FIG>.

Furthermore, two retaining elements <NUM> which are amalgamated in a third pair <NUM> and which are at a distance a' from one another can be seen in the right part of <FIG>. A fourth pair <NUM>, which is not identifiable as such in <FIG> but which can also be easily understood taking into account the left part of <FIG> and <FIG>, is located on the opposite side of the contact pin <NUM> which is not depicted, in a symmetrical arrangement relative to the longitudinal axis x.

As is inferred from <FIG> and also <FIG>, the first distance a is greater than the second distance a', the first pair <NUM> and the third pair <NUM> as well as the second pair <NUM> and the fourth pair <NUM> being arranged such that, in the event that the positions of all the retaining elements <NUM> are projected onto the y-z plane, as shown in <FIG>, the projections of the third pair <NUM> are located centrally between the projections of the first pair <NUM>, and the projections of the fourth pair <NUM> are located centrally between the projections of the second pair <NUM>.

<FIG> also shows that when the positions of all the retaining elements <NUM> are projected onto the y-z plane, the following applies:
There are no two retaining elements <NUM> which have positions in the y-z plane which are located on a common connecting line with the origin U, provided that the origin is not located between the positions of the retaining elements <NUM> on the connecting line.

Furthermore, at least two angular ranges W2 based on the origin as the vertex exist in the y-z plane, in which no retaining elements <NUM> are arranged, W2 respectively being greater than <NUM>° in the depicted exemplary embodiment.

By means of the arrangement of the angular ranges W2, in which no retaining elements <NUM> or their projections are located, and by means of the relatively large extension of these angular ranges along the surface of the contact pin <NUM>, a delimitation of the assembly force to be applied for assembling the pin strip with a contact pin <NUM> is ensured.

Furthermore, as indicated in the right part in <FIG>, the inventive arrangement of the retaining elements <NUM> on the base body ensures that each retaining element <NUM> touches at least partially undamaged base material of the pin strip, whereby all retaining elements provide an approximately equal contribution to the retention force.

In <FIG>, in this context, the lines of action, along which retaining elements <NUM> that are each arranged successively provide their contribution to the total retention force, are depicted as a region B1 and a region B2. The retention force thus becomes approximately constant along a large part of the withdrawal path.

Claim 1:
A contact pin (<NUM>) for a plug connector, comprising a base body (<NUM>) with a longitudinal axis (x) and a surface (O),
wherein a first end of the contact pin (<NUM>) is adapted to be plugged into an opening of a pin strip of a plug housing of the plug connector,
wherein the contact pin (<NUM>) has at least four retaining elements (<NUM>) moulded on the base body (<NUM>), wherein two retaining elements (<NUM>) are each arranged successively spaced apart along the longitudinal axis (x), wherein two retaining elements (<NUM>) are further each arranged oppositely at the same point of the longitudinal axis (x) in the circumferential direction, and
wherein the retaining elements (<NUM>) arranged successively are arranged in the circumferential direction at an angle (W1) offset from one another,
characterised in that
the angle (W1) is smaller than <NUM>°,
wherein the retaining elements (<NUM>) are formed, with respect to their number and their dimensions, such that a retention force of the contact pin (<NUM>) from the pin housing reaches a value greater than or equal to <NUM> N.