Abstract:
A device and method facilitates grounding shielding, including hardware and structures necessary to allow proper connection, practice the steps of the method, minimize pigtail length, facilitate the formation of a wire bundle assembly, facilitate repair and installation, and result in materials and labor savings.

Description:
BACKGROUND OF THE INVENTION 
     Industry has long used various types of electrical wiring and interconnects. These frequently employ shielding which covers the individual wires. This shielding is intended to provide an electromagnetic barrier between the shielded wire and other wires or the electromagnetic environment. These shields cannot perform their intended function if they are not electrically teminated in a mechanically and electrically suitable manner. 
     Shielding a permanent section of line can be accomplished in a cost effective manner during the manufacturing operation. However, where connectors are concerned, it may be mechanically convenient to break the grounding shield to facilitate connection and reintroduce the shield on the other side of the connector. This produces a gap in the shields covering of the wire bundle, and thus degrades the ground shield&#39;s electrical effectiveness. 
     Presently, the wire grounding hardware will usually consist of grounding studs such as a screw, nut and washer, which must be mounted on an adequately conductive surface. The grounding wire is terminated in lugs with a round hole which must be placed over the ground stud screw and held in place using the nut and washer. Assembly requires larger working space and good dexterity. For reasons of mechanical access, the ground stud must usually be located a minimum of several inches from its associated electrical connector. 
     Other methods utilize a special back shell for the electrical connectors. These are an improvement on ground studs, but the method of mechanically terminating the wire or shield in these special back shells differs from the method used to terminate the wires at the connector. The use of the back shell requires special training and handling practices and procedures. Disassembly and reassembly of these grounded connections for repair or trouble shooting is very difficult. 
     Normally when the shield is interrupted, the ground shield is grounded to the support structure, which in aerospace applications is typically an airframe. The length of the connection from the ground shield interrupt to the airframe, also known as the pigtail, is an important consideration. Long pigtails and poorly chosen grounding points can seriously degrade the ground shielding to the point of negating the usefulness of the ground shield. 
     SUMMARY OF THE INVENTION 
     The device and method for grounding of the present invention provides a proper grounding termination for a wide variety of grounding. The device and method disclosed herein can be utilized and fully implemented in wire termination hardware of many types. 
     The device and method of the present invention holds the pigtail to the minimum necessary to allow for the proper grounding connection and, indeed, facilitates the availability of that shorter length. In most cases, the use of the invention will allow limitation of the pigtail to no longer than the length of the unshielded main connector through the connector. 
     The device and method of the present invention also facilitates wire bundle assembly, of which the shielded wire is a part, to flex more freely about the rear area of the connector. Alternately, the wire bundle can be moved with the connector for ease of assembly, installation and repair because it is now free of the grounding connection to a fixed ground frame surface. 
     An important practical aspect of the invention is use of commonly available electrical disconnect devices and tooling usually identical to those used to terminate the wires in the connector. Aside from the basic shield grounding plate assembly of the invention, no new parts, tools or training methods are required to implement the apparatus and method of the present invention. Therefore, the resulting system will be user friendly and electromechanically effective. The use of the present invention will result in materials and labor savings and offer greater utility to the electrical connector environment. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The structure and method of operation of the invention, together with additional advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which: 
     FIG. 1 is an isometric view of the mating parts of a typical connector utilizable in implementing the present invention; 
     FIG. 2 is an isometric view of the connector of FIG. 1 in mated alignment; 
     FIG. 3 is a side view of a shielded wire approaching the electrical connector of FIGS. 1 and 2 illustrating the method of grounding attachment; and 
     FIG. 4 is an isometric view of a typical wire bundle connected to the typical connector of FIG. 1. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIG. 1, an isometric view of the mating parts of a tyical connector utilizable in implementing the present invention is shown. A shield grounding block 101 is shown in elevated position. Mounting holes 103 are provided for the attachment of shield grounding block 101. Isometrically above shield grounding block 101 is a connector 105. 
     For the attachment of shield grounding block 101 to connector 105, shield grounding block 101 is provided with a grounding plate and insert retainer 107. Further, shield grounding block 101 has a grounding contact cavity 109. Connector 105 has a power contact insert 111. Connector 105 has a threaded hole 113 to anchor the shield grounding block 101. A grounding aperture 115 is provided on connector 105 to enable the grounding potential to be accepted by connector 105. Also on connector 105 is located a signal contact cavity 117. 
     Referring to FIG. 2, an isometric view of a shield grounding block connected to a typical connector as was illustrated in FIG. 1 is shown. Into grounding shield block 101 a typical mounting screw 119 is inserted through a typical lock washer 121. A multiplicity of these are used to join shield grounding block 101 to connector 105 at various points about their peripherae. 
     Referring to FIG. 3, a side view of a shielded wire approaching the electrical connector of FIGS. 1 and 2 illustrating the method of grounding attachment is shown. A shielded wire 123 extends from a point outside of FIG. 3, downward. Shielded wire 123 can have any type of shielding, but will normally have a braided shielding as is illustrated. A shield crimp termination 125 is illustrated on shielded wire 123 at the point of shielding termination. Electrically attached to crimp termination 125 is a grounding conductor 127. Grounding conductor 127 will typically have an insulated section 129. Grounding conductor 127 typically terminates in a crimp end 131 of a socket contact 133. 
     The conductor which is shielded up to shield crimp termination 125 will be referred to as signal wire 135, although this line need not necessarily carry a signal. Signal wire 135 also terminates in a crimp end 131 of a pin contact 149. Upon installation, pin contact 149 will extend through a connector insert 137. This condition is illustrated in the right half of FIG. 3. Pin contact 149 is illustrated as well within connector insert 137. 
     Referring to the left half of FIG. 3, a retainer bushing 139 is shown below and parallel to socket contact 133. Immediately above retainer bushing 139, a retainer clip 141 is shown. Below retainer bushing 139, a grounding pin 143 is shown. At the right hand side of FIG. 3, pin contact 149 is shown inserted into retainer bushing 139 and held in place by retainer clip 141, acting against the raised radial land portion of socket contact 133. 
     Referring to FIG. 4, an isometric view of a typical wire bundle connected to the typical connector of FIG. 1 is shown. An avionic rack section 145 is shown as a point of reference. To the avionic rack section 145 is attached connector 105 to which is attached the shield grounding block 101 shown on FIGS. 1-3. Shield grounding block 101 extends through a cut-out portion 147 of avionic rack 145. A typical cable harness 151 is shown entering the perspective of FIG. 4 from the upper left hand corner. This harness 151 contains many wires, among which are several shielded wires 123. 
     FIG. 4 illustrates the grounding connection of three shielded wires 123. Note that the shield grounding pigtail 129 of each shielded wire 123 is connected to a point about the periphery of shield grounding block 101, while the signal wire 135 is connected nearer the center, through one of the connector inserts 137. Shield grounding block 101 is held in place on avionic rack section 145 by a pair of connector mounting holes 153 located at the top and bottom of avionic rack section 145. 
     The forgoing disclosure and description of the invention are illustrative and explanatory thereof, and various changes in the size of the grounding block 101, orientation of the wiring, materials of construction, physical configuration, and changes to effect the desired electromagnetic performance characteristics to be achieved, as well as in the details of the illustrated embodiments, may be made without departing from the spirit and scope of the invention.