Abstract:
A terminal assembly and terminal installation. In one embodiment, the terminal assembly includes a body having a longitudinal opening therethrough and a shoulder. The terminal assembly is installed in an aperture adapted to receive and join the body to a wall with a joining process material. The terminal assembly includes a current-conducting pin extending longitudinally through the opening in the body, and a dielectric seal between the body and the pin. The shoulder of the body is configured to prevent the migration of debris toward the pin during installation.

Description:
FIELD OF THE INVENTION 
   The present invention relates to a terminal installation and a terminal assembly. 
   BACKGROUND OF THE INVENTION 
   Installations of low power terminal assemblies are well known in the art. Terminal assemblies, such as the prior art assembly illustrated in  FIG. 1 , typically include one or more current-conducting pins  5  that are secured to a metallic body  7  by a glass-to-metal seal  9 . The body  7  is installed and sealed into an opening  6  defined in a wall  3 . 
   A durable seal between the body and the opening in the wall is desirable to maintain the integrity of the feed-through under elevated stress and temperature conditions without causing breakage between the body and the opening in the wall. It is also important to provide an optimum air path between adjacent portions of the conductive pin and the opening in the wall in order for the conductive pin to be operably coupled with an external device. 
   On occasion, the conductive pins of prior art terminal assemblies, such as the one illustrated in  FIG. 1 , become contaminated during installation, when the body  7  is soldered or otherwise secured into the opening  6  of the wall  3 . Specifically, as solder fills the opening  6  between the body  7  and the wall  3 , an overflow of solder or other joining process material may leave the opening  6  in an arc-like manner coming in contact with portions of the conductive pin  5 . 
   There is a need for a terminal assembly that eliminates the potential of contamination of the conductive pin during installation. 
   SUMMARY OF THE INVENTION 
   The invention provides a terminal installation and a terminal assembly. In one embodiment, the terminal assembly includes a body that has a longitudinal opening and a shoulder. The terminal assembly is installed in an aperture adapted to receive and join the body to a wall with a joining process material. The terminal assembly includes a current-conducting pin that extends longitudinally through the opening in the body, and a dielectric seal between the body and the pin. The shoulder of the body is configured to prevent the migration of debris, such as an overflow of joining process material, toward the pin during installation of the terminal assembly. 
   Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention can be better understood with reference to the following drawings and description. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. Moreover, in the figures, like reference numerals designate corresponding parts throughout the different views. 
       FIG. 1  is a cross-sectional front view of a prior art terminal installation showing an unprotected air path between a conductive pin and a wall; and 
       FIG. 2  is a cross-sectional front view an embodiment of a terminal installation according to the invention showing a protected air path between a conductive pin and a body having a shoulder. 
   

   DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
   The following description of the preferred embodiments is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. 
     FIG. 2  illustrates an embodiment of a terminal installation  10  according to the invention. A terminal assembly  11  is installed in an aperture  22  defined in a supporting structure (herein after “the wall”)  16 . The aperture  22  is adapted to receive the terminal assembly  11  using a joining process, such as, for example, brazing, soldering, adhesive bonding, etc., which fills the space between the aperture  22  and the terminal assembly  11  with a joining process material  58 . The joining process material  58  may be a filler metal for soldering or brazing processes, or any type of adhesive, such as epoxy, for adhesive bonding. The terminal assembly  11  comprises a conductive pin  12  that has first and second portions  30 ,  32 , a body  14  having an outer surface  54 , and a dielectric seal  34 . The body  14  includes first and second portions  42 ,  44 . 
   The dielectric seal  34  is annular and encloses the first portion  30  of the conductive pin  12 . The dielectric seal  34  may be made of a glass matrix composed chiefly of silicates and an alkali substance. It should be understood, however, that the glass matrix may include other substances such as, for example, oxides. The dielectric seal could also be made from other materials, including plastic, polymers, cured epoxy, etc. 
   The body  14  includes a shoulder  46  between the first and second portions  42 ,  44 . The shoulder  46  may include an inner lip  48  and an outer lip  50 . The dielectric seal  34  is disposed between the first portion  42  of the body  14  and the first portion  30  of the pin  12 , and is partially seated on the inner lip  48  of the body  14 , such that an inner annular portion  52  of dielectric seal  34  is not seated on the inner lip  48  of the body  14 . The annular portion  52  creates a gap  20  having width “d” and providing an air path between the second portion  32  of the conductive pin  12  and the second portion  44  of the body  14  to allow an electric component (not shown) to be connected to the conductive pin  12 . It should be understood that the magnitude of the width “d” is variable and may be modified according to the particular application for the terminal assembly. 
   The body  14  is made of a low expansion metal alloy, such as, for example, Kovar®. The body  14  and the dielectric seal  34  are sealed to each other using glass-to-metal sealing methods well known in the art. It should be understood that the body  14  may be made of any low expansion metal alloy that can be used in applications that require glass to metal sealing. 
   The aperture  22  in the wall  16  is adapted to receive the body  14  and join the body  14  to the wall  16 . Therefore, the aperture  22  conforms with the outer surface  54  of the body  14 , such that the aperture  22  includes a shoulder portion  56  corresponding to the shoulder  46  of the body  14 . In one embodiment, the shoulder portion  56  of the aperture  22  may have a step that matches the outer lip  50  of the shoulder  46  of the body  14 . The body  14  is secured to the aperture  22  using a joining process that fills the aperture  22  with joining process material  58 , which may be, for example, solder. The joining process joins and secures the body  14  to the aperture  22  of the wall  16 . In addition, a groove  24  may be defined at the uppermost portion of the aperture  22  between the wall  16  and the first portion  42  of the body  14 . The groove  24  is also filled with the joining process material  58 . 
   It will be appreciated that depending on the joining process used, the joining process material  58  may be injected into the aperture  22 , inserted and heated until it flows to fill the space between the aperture  22  and the body  14 , following the contours of the shoulder  46  of the body  14  and the shoulder portion  56  of the aperture  22 . The joining process material  58  fills that space for the entire length of the aperture  22  and the groove  24 . Any excess amount of the joining process material  58  flows parallel to the second portion  44  of the body  14 , thereby eliminating the potential of debris  59  from joining process migrating into the gap and contaminating the conductive pin  12 . The body  14  and the aperture  22  in the wall  16  are securely joined together, thereby completing the installation of the terminal assembly  11 . It should be understood that the joining process material  58  that fills the aperture  22  may be any type of material capable of securing the body  14  in the aperture  22 . The joining process and the joining process material  58  may also be selected to provide a hermetic seal between the body  14  and the wall  16 . 
   The structure of the terminal assembly  11  of the present invention eliminates the potential of debris  59  from the joining process material  58  migrating toward and contaminating the conductive pin  12  during installation. In addition, the structure of the terminal assembly  11  can provide an effective hermetic seal between the body  14  and the aperture  22  in the wall  16 , which will enable the terminal assembly  11  to withstand elevated stress and temperature conditions without experiencing breakage between the body  14  and the aperture  22 . 
   While various embodiments of the invention have been described, it will be apparent to those of ordinary skill in the art that other embodiments and implementations are possible that are within the scope of this invention. Accordingly, the invention is not restricted except in light of the attached claims and their equivalents.