Abstract:
A screening arrangement for a multi-pin cable connector in which a known connector formed of synthetic material is screened by the use of a metal liner which is simply pressed into position within opposite halves of the known connector. The liner provides a low ohmic contact of the cable screen with the associated apparatus to which it is connected as well as suitable screening of the interior of the connector housing.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The field of art to which this invention pertains is multi-pin cable connectors and in particular to means for screening such cable connectors against electromagnetic waves. 
     2. Description of the Prior Art 
     In cable connectors the associated cable of which is itself provided with a screen, the problem arises on the one hand of connecting the cable screen through the plug-in connector, with the electrical apparatus to which the connector is fitted, and on the other, of screening the connector housing itself against electromagnetic waves. In order to connect the cable screen through to the associated apparatus, it is known from German &#34;Offenlegungsschrift&#34; No. 2 123 053 as laid open for inspection, to introduce special measures into the connector itself, by means of which a determinate resistance is created between the screen and the connected apparatus. A precondition, however, is that the housing of the cable connector itself must be made of a metal material so that contact between the cable screen and the associated apparatus, can be established through the housing itself. 
     If, however, the housing of the cable connector is made of synthetic material, then this solution cannot be employed. 
     SUMMARY OF THE INVENTION 
     It is a principal object of the present invention, considering known cable connectors having synthetic housings, to provide simple means for connecting the cable screen through to the associated apparatus and at the same time to effect screening of the interior of the cable connector generally. 
     A more specific object of the present invention is to provide that the internal walls of the halves of the synthetic material housing are each lined with a metal liner. 
     It is a further object of the present invention that each half of the synthetic material housing has a metal bracket fitted into it between which the cable screen can be clamped. 
     It is also an object of the invention to provide a device as described above wherein the metal liner is so formed that there is a low-ohmic connection between it and the metal bracket, as well as between the latter and the pin base. 
     It is also an object of the present invention to provide a metal liner as described above incorporating projecting spikes, which when the liner is fitted into position, hook into the halves of the synthetic material housing. 
     Another object of the present invention is to provide metal brackets for a connector which are of spring design so that with the connector assembled the cable, and therefore the cable screen, are held firmly between the metal brackets in the two halves of the connector, and in which the connector disassembled, the metal brackets are self-retaining and do not drop out of the housing. 
     These and other objects, features and advantages of the present invention will be understood from the following description and the associated drawing wherein reference numerals are utilized to designate a preferred embodiment. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     FIG. 1 is an exploded view of a known cable connector with the screening arrangement in accordance with the invention. 
     FIG. 2 is a detailed illustration of the metal liner in accordance with the invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The present invention relates to a screening arrangement for a multi-pin cable connector, with a synthetic material housing in the form of two halves and a metal pin base. 
     An advantage of the present invention resides in the fact that by simply re-equipping a known kind of multi-pin cable connector with an easily produced metal liner in each half, not only is the connector housing itself screened but also reliable contacting of the cable screen with the associated apparatus is established, via the connector. 
     FIG. 1 illustrates the known cable connector which consists of the two identical halves 1 and 1a and the pin base 6. The pin base 6 is placed in corresponding retainer elements at the front of the two halves 1 and 1a, and held in position by screwing together the two halves 1 and 1a. In a manner which has not been illustrated, the individual wires of the cable 5 are connected to the pins of the pin base 6 so that said wires pass loosely through the connector housing and are only combined together at the point where they exist from the connector housing, by the cable clamp 7. 
     Because the two halves of the connector housing, 1 and 1a, consist of synthetic material, in order to screen the interior of the connector in accordance with the invention, a metal liner 2 is fitted into each half of the connector housing. This liner 2 is so designed that it covers the entire horizontal interior section of the two halves 1 and 1a. Moreover, it extends into the rear zone of the housing halves, where there is a recess. In said recess, a metal bracket 3 is fitted in such a fashion that the vertical, lateral ends of the bracket act as springs, the bracket being clamped in position in the opening. In so doing, the ends of the bracket 3 are placed in contact with the metal liner 2 and thus form a low-ohmic electrical contact therewith. This metal bracket 3, in association with the second metal bracket in the top half of the connector, forms a kind of cable clamp which acts to establish contact with the screen 8 on the cable 5. In addition, the bared cable screen 8, is introduced into the connector housing 1 and 1a to such an extent that it is clamped precisely between the two brackets 3 in upper and lower halves of the connector when said halves are screwed together. In this fashion, a low-ohmic electrical connection from the cable screen 8 via the two brackets to the metal liner 2 in the two halves of the connector is established. 
     To establish contact between the cable screen 8 and an electrical apparatus (not shown) to which the connector is connected, the metal liner 2 is provided at the front end of the connector with additional tags 9 which are bent over the left-hand and right-hand external portions of the connector halves 1 and 1a. As FIG. 1 shows, these tags 9 of the metal liner 2 are so disposed that the metal pin base 6 fitted into the halves of the connector housing when the connector is assembled, comes into contact with the tags 9. In this fashion, a low-ohmic electrical connection is established between the metal liner 2 and the metal pin base 6 so that overall there is a low-ohmic connection from the cable screen 8 of the cable 5, via the two brackets 3 and the liner 2 to the pin base 6. Because the pin base 6 is connected to appropriate screening arrangements of the associated electrical apparatus, for example, has good electrical contact with the apparatus housing itself, the desired effect of contact between the cable screen 8 and the apparatus is thus achieved. 
     An accurate illustration of the metal liner 2, all parts thereof having been shown in the same plane, is to be found in FIG. 2. The external dimensions of the metal liner 2 correspond to the internal dimensions of the halves 1 and 1a of the connector housing. FIG. 2 illustrates the simple and advantageous method of attaching the metal liner in each case to one half of the connector. For this purpose, at four locations on the external edge of the metal liner 2, a metal spike 4, is provided, the tip of which projects beyond the actual profile of the liner 2. When the liner 2 is fitted into one of the halves 1, 1a of the connector, these spikes 4 hook into the synthetic material wall thereof. In this fashion, the metal liner 2 can be assembled quite simply, and also reliably secured against dropping out. FIG. 2 also shows how the metal liner 2 complete with the tags 9 can be manufactured in one piece, for example by punching, and how the tags 9 can be given the requisite form by a simple bending operation.