Patent Publication Number: US-5026295-A

Title: Cover for an electrical connector

Description:
FIELD OF THE INVENTION 
     This invention generally relates to the art of electrical connectors and, particularly, to a cover for closing an open cavity in an electrical connector to protect interior terminals during processing, such as during wave soldering processes. 
     BACKGROUND OF THE INVENTION 
     A wide variety of electrical connectors are used for mounting on printed circuit boards to connect terminals on the connectors to circuit traces on the boards. One type of electrical connector, commonly called a header, includes an elongate, rectangular housing having side walls defining an upwardly opening cavity. Terminal pins are disposed in the cavity, with solder tails projecting through a bottom wall and through holes in the printed circuit board for soldering to circuit traces on the printed circuit board. 
     Often, connectors of the character described have a polarizing slot in a side wall of the housing to insure proper relative orientation of the terminal pins with contacts of a complementary mating connector. In other words, the terminal pins within the housing cavity are exposed through the polarizing slot in the housing side wall. 
     Such polarizing slots cause problems during soldering processes, particularly when the connector is located or mounted on the printed circuit board at a location near the edge of the board. During a wave soldering process the terminals within the housing cavity are susceptible to contact with the solder material which could enter through the polarizing slot. 
     Heretofore, the predominant solution to the aforesaid problem of contaminating the interior terminal pins with solder material has been to close the housing cavity with a cover which is removed after soldering, and to keep the polarizing slot closed with a continuation of the housing side wall which is scored along lines which define the polarizing slot. After soldering, a portion of the side wall is punched out, along the scoring lines, to leave the open polarizing slot for its intended purpose. However, such procedures not only require an additional assembly step during fabrication of the printed circuit board assembly, but removing of a portion of the side wall defining the polarizing slot, after soldering, creates forces which can damage the solder connections and/or damage portions of the connector housing or the terminals themselves. 
     This invention is directed to solving these problems by closing the polarizing slot, during the soldering process, by the same cover that closes the cavity of the connector housing. 
     SUMMARY OF THE INVENTION 
     An object, therefore, of the invention is to provide a new and improved cover for temporarily closing a cavity of a polarized electrical connector to protect the terminals therein during a soldering process or the like. 
     In the exemplary embodiment of the invention, the cover is designed for use with an electrical connector in the form of a header for mounting on a printed circuit board. The header has a cavity defined by side walls and a bottom wall. Terminal pins are disposed in the cavity, with solder tails projecting through the bottom wall and through holes in the printed circuit board for soldering to circuit traces on the printed circuit board. At least one polarizing slot is provided in the side walls of the header. 
     The invention contemplates a cover for closing the header cavity to protect the terminals during a soldering process. The cover includes a lid and complementary interengaging means between the lid and the header side walls for positioning the cover on the header to close the cavity. Projection means are provided on the lid, depending therefrom, for closing the polarizing slot in the side walls. Therefore, after soldering, the cover is removed to open the cavity and, at the same time, to open the polarizing slot. No further steps or procedures are required and the assembly is complete for mating the header with a complementary connector. 
     A feature of the invention is to provide a pair of the projection means depending from opposite sides of the lid of the cover to close the polarizing slot regardless of the orientation of the cover. 
     Other objects, features and advantages of the invention will be apparent from the following detailed description taken in connection with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The features of this invention which are believed to be novel are set forth with particularity in the appended claims. The invention, together with its objects and the following description taken in conjunction with the accompanying drawings, in which like reference numerals identify like elements in the figures and in which: 
     FIG 1 is a perspective view of an electrical connector in the form of a header mounted along an edge of a printed circuit and including a cover incorporating the concepts of this invention; 
     FIG. 2 is a side elevational view of the cover; 
     FIG. 3 is an end elevational view of the cover; and 
     FIG. 4 is a bottom plan view of the cover. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to the drawings in greater detail, the invention is directed to a cover, generally designated 10, for closing a cavity, generally designated 12 (FIG. 1), and a polarizing slot 14 of an electrical connector in the form of a header, generally designated 16, during a soldering process when the header is mounted on a printed circuit board 18. 
     As shown in FIG. 1, header 16 is of a conventional configuration in that it is generally rectangular, elongated and includes side wall means defining cavity 12. The side wall means include opposite side walls 20a and 20b and end walls 22. A plurality of terminal pins 24 are disposed in cavity 12, with solder tails 26 projecting through a bottom wall 28 of the header. When the header is mounted on printed circuit board 18, solder tails 26 project through appropriate holes (not shown) in the board for soldering to circuit traces on a bottom side 30 of the board. Conventionally, the soldering is done by a wave soldering process. 
     It can be seen in FIG. 1 that header 16 is mounted along an edge 32 of printed circuit board 18, and that polarizing slot 14 in side wall 20a is open along that edge. Such edge mounting is quite common to make efficient use of an entire printed circuit board, and the disposition of the polarizing slot at an edge often is unavoidable because of the arrangement of the circuitry of the board. As stated above, such an arrangement causes problems because of the susceptibility of the soldering material entering the polarizing slot and contaminating the interior of the header, particularly the susceptibility of the soldering material contacting terminal pins 24. 
     Heretofore, the predominant solution of protecting the interior of header 16 has been to close cavity 12 with a temporary cover and to close polarizing slot 14 with a scored portion of side wall 20a which is punched out after the soldering process. 
     Referring to FIGS. 2-4 in conjunction with FIG. 1, cover 10 includes a generally planar lid 12 which is rectangularly shaped complementary to the shape of header 16 and is sized larger than cavity 12 to overly and seat upon an upper edge 34 of side wall means 20a, 20b, 22 completely surrounding cavity 12. A rectangular flange 36 depends from lid 12 and is of a size and shape to press fit into cavity 12 immediately below upper edge 34. 
     In order to facilitate positioning cover 10 onto header 16 to close cavity 12, a pair of end tabs 38 are provided for positioning within end walls 22 of the header. It can be seen in FIG. 2 that the tabs are chamford, as at 38a, to guide the cover into position to close the cavity. 
     In order to facilitate removal of cover 10 after a soldering process, outwardly projecting tabs 40 are provided intermediate the ends of lid 12 for grasping by one&#39;s fingers to lift the cover off of the header. 
     The invention contemplates at least one projection 42 depending from lid 12 for closing polarizing slot 14 in side wall 20a to prevent any soldering material from entering the header cavity through the slot. In the illustrated embodiment, projection 42 actually depends from the bottom edge of flange 36 as a continuation thereof. The entire cover is integrally molded of plastic material. 
     When cover 10 is properly positioned on header 16 to close cavity 12 and polarizing slot 14, a bottom edge 42a (FIG. 2) of projection 42 seats onto the top of bottom wall 28 of the header to insure that no soldering material seeps into the header cavity. The width &#34;W&#34; (FIG. 2) of projection 42 is wider than polarizing slot 14 so that the projection overlies an area of side wall 20a inside cavity 12, again to provide a good barrier against migration of soldering material into the cavity. 
     It can be seen in FIGS. 3 and 4 that cover 10 actually is provided with two projections 42 on opposite sides of cover 10. The pair of projections are provided to close the polarizing slot regardless of the orientation of the cover. In other words, such connectors are miniaturized and by providing a pair of projections, an individual who is assembling the printed circuit board does not have to manually manipulate and switch-around the cover during assembly to insure that the polarizing slot is closed. Providing two projections also is an insurance measure so that it is impossible to position the cover on the header without closing the polarizing slot. 
     It will be understood that the invention may be embodied in other specific forms without departing from the spirit or central characteristics thereof. The present examples and embodiments, therefore, are to be considered in all respects as illustrative and not restrictive, and the invention is not to be limited to the details given herein.