Abstract:
A modular jack for telephone and data equipment test access ports including a cover having substantially the same thermal coefficient of expansion as its housing, and which is integral with the housing to prevent its being lost during usage or testing. The cover extends inwardly of the housing, to rotate further inwardly, automatically, upon the insertion of the plug into the housing to complete the electrical circuit.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to the testing of telephone lines, in general, and to the testing of such lines as used in voice and data transmission for both personal and business users, in particular. 
     2. Description of the Related Art 
     With the advent of deregulation in the telephone industry has come the need to determine whether a problem on a line is external to a structure (and, therefore, the obligation of the telephone company to correct) or internal to the structure (and, thusly, the responsibility of the end-user to deal with). Network interface devices developed to address this concern commonly employ anywhere from 1 to 200 modular jacks as test access ports, depending upon whether the monitoring is of a line that may be present in a residence, or at a business location. Whether or not the modular jack is of an RJ 11 type carrying 2 conductors, or whether it is of an RJ 45 type carrying 8 or 9 conductors, and whether or not the network interface devices additionally incorporate such other features as surge suppression or lightning, over-current or over-voltage suppression controls, the ever increasing competition in the telephone industry requires that the costs associated with these devices be kept as low as possible. These costs include, not only the manufacturing costs of the units, but the installation costs, as well, in addition to the costs connected with their actual use in testing the problem on the line. 
     SUMMARY OF THE INVENTION 
     One area of investigation—leading to the present invention—for keeping these various costs low deals with the modular jacks employed, themselves. More specifically, at present, these modular jacks are provided as two separate pieces, the jack and its cover, which then must be fitted together. Besides the labor cost associated with joining the pieces, this type of manufacture militates against the savings inherent if the manufacture and fitting were automated. Secondly, testing has shown that during thermal cycling—even over as little a temperature change as 30° occurring during a typical day—the coupling between the installed cover and its underlying jack can range between a snug fit and a very loose one, impairing the degree of securement desired. Analysis has indicated that this results from the different temperature coefficients of expansion between the hard plastic jack and the rubberized polymer material employed for the cover. As a result, frequently, a service technician accidently drops the cover when accessing the jack, and has to search for it in the grass and/or leaves present at an outdoor location for the network interface device—thereby, unnecessarily adding to the labor costs of testing a line. Moreover, even in those circumstances where the cover does not separate from the jack, the typical operation is for the technician to hold the cover open with one hand, accessing the test port with his electrical plugs and tools with the other hand, all the while balancing the test equipment against his, or her, body; this, too, ultimately adds to the time spent in testing the cause of the on-line problem, adding to the costs of responding to, and servicing the customer&#39;s complaints. Were all this not enough, another oftentimes overlooked expense for the telephone company is present and to be factored in—namely, the inventory control and re-ordering requirements needed for the two separate items of the jack and its cover. 
     While an obvious answer might be the simple “doing away with” of the cover, field use has shown the need for the cover when the network interface device is used outdoors, or in other harsh environments, where otherwise exposing the modular jack to dust, rain, and the other elements causes problems up to, and including the short-circuiting of the telephone line, and the loss of all connections. To prevent this from happening—and even though all these other costs incidental to the modular jack are present—the continuing use of a cover to protect and seal the modular jack is necessary. 
     As will become clear from the following description, these problems of the prior art are addressed by the modular jack of the present invention for use with telephone and data equipment testing. As will be seen, the jack of the invention includes a housing incorporating a plurality of contact wires for completing an electrical circuit when receiving a plug inserted through an opening in the housing, along with a cover sealing the opening when the plug is not inserted, as in the prior art. However, in accordance with the invention, the cover is fabricated as an integral part of the housing—and not separate from it—, and further is of the same substantial composition as the housing to exhibit substantially the same thermal coefficient of expansion. In making the cover an integral part of the housing (so as to capture it, and so that the cover is not lost during testing), a hinge is provided to join the cover and housing together and, preferably, a spring type hinge. 
     In one embodiment of the invention to be described, the integral cover will be seen to extend outwardly of the housing in sealing its opening when the technician&#39;s plug is not inserted, to be rotated further outwardly and away from the opening when the cover is first manually lifted, for the insertion of the electrical plug. In a second embodiment, the cover will be seen to extend inwardly of the opening, sealing it when the plug is not inserted, and to be rotated further inwardly of the opening as the cover is automatically lifted through the insertion of the plug into the housing. With both the housing and the cover in these two embodiments formed of a hard plastic material, the same thermal coefficients of expansion are present, so that the cover does not loosen with temperature cycling during environmental use. By having the cover integral with the housing, the covers cannot get lost in the field—which saves the replacement cost of the cover and the time to obtain replacements for it, and extends the overall life of the modular jack itself. By further fabricating the housing and cover of a hard plastic material, and as an integral part, further savings inherent in an automation manufacture and assembly follows, in further keeping costs low. Thus, obviously, with only one part to deal with, inventory control is simplified, and the cost of ordering eased. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other features of the present invention will be more clearly understood from a consideration of the following description, taken in connection with the accompanying drawings in which: 
     FIG. 1 is a perspective view of a modular jack for a telephone and data equipment test access port constructed in accordance with the prior art; 
     FIGS. 2 a  and  2   b  are sectional views helpful in an understanding of a first embodiment of the invention in which an integral cover extends outwardly of the jack in sealing the housing when the test plug is not inserted, and rotates further, outwardly and away from the opening when the cover is manually lifted to insert the plug, respectively; and 
     FIGS. 3 a  and  3   b  are sectional views helpful in an understanding of a second embodiment of the invention in which the integral cover extends inwardly of the modular jack in sealing the housing when the test plug is not inserted, and which is rotated further inwardly, and automatically lifted, by the insertion of the plug into the jack, respectively. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The modular jack of the prior art is shown in FIG. 1 with its opening  12  exposing the contact wires  14  included within its housing  15 , to be connected with an inserted electrical plug (not shown), as a test access port. Typically fabricated of a hard plastic material, the jack is sealed by a separate cover  16  fitted over the housing  15  at the opening  12 , and usually of a rubberized polymer material. When the electrical plug is to be inserted, the cover  16  is removed from the opening  12 . After the testing has completed and the plug removed, the cover  16  is replaced. 
     In the cross-section view of FIG. 2 a , a cover  18  is hinged at  20  integral with the housing  15 , when fabricated together as a single, hard plastic molded part—and, preferably, through an automated process. In the “closed” position of FIG. 2 a , a dimple  22  on the cover  20  fits within an aperture  24  on the housing  15  so as to lock the cover  18  in place in sealing the jack when no electrical plug is to be inserted. With a handle  26  extending upwardly from the cover  18 , the cover  18  is rotatable outwardly away from the opening  12  when the cover  18  is first manually lifted away by the servicing technician to facilitate insertion of the electrical test plug into the opening  12 . By having the hinge  20  in the nature of a spring hinge, the cover  18  remains substantially in the position shown in FIG. 2 b , as the electrical plug is being inserted. This frees one hand of the technician, allowing the other hand to hold the test equipment without any need for balancing it against the body. Simple to manufacture, the spring hinge  20  is biased for closing the opening  12  by pushing the handle  26  in the direction shown by the arrow “A”, the arrow “B” showing the rotation to open the cover  18 . 
     Whereas the embodiment of the invention illustrated by FIGS. 2 a  and  2   b  is particularly attractive for a network interface device connected externally of a personal residence—as where only one or at most a few modular jacks for test access are provided—, the embodiment illustrated by the sectional views of FIGS. 3 a  and  3   b  prove quite attractive for use in high density business areas, where upwards of 50, 100, and even up to 200 telephone lines are incorporated, as in business entrance terminal and/or business entrance protector network interface devices (where the tightness of space makes it awkward for the technician to lift the cover of the jack through finger manipulation). In the arrangement of FIGS. 3 a  and  3   b , the integral cover  30  extends inwardly of the opening  12  in sealing the opening when the plug is not inserted (FIG. 3 b ). The hinge coupling with the housing  15  is shown at  32 , again preferably of a “spring” construction. A rib  33  molded on the inside of the housing  15  serves as a “stop” in setting the quiescent position for the cover  30  when the electrical plug is not present. Inserting the plug  34  automatically lifts the cover  30  in the direction shown by the arrow “C”, rotating the cover  30  further inwardly to the position shown in FIG. 3 a  when the plug  34  is fully inserted. A slot  38  in the plug  34  may be provided to overlay the rib  33  in defining the fully inserted position for the plug  34 , at which point the electrical connection with the contact wire  14  is completed. Reference numerals  40 ,  42  in FIG. 3 a  identify the leads back to the technician&#39;s test equipment (not shown). 
     As with the embodiment of FIGS. 2 a  and  2   b , the cover  30  and the housing  15  of FIGS. 3 a  and  3   b  are fabricated of a hard plastic material, exhibiting a common temperature coefficient of expansion to continue unchanged their initial fit during temperature cycling, while continuing to seal the jack against dust, rain, snow, etc. in protecting against such environmental conditions as might deleteriously affect the user&#39;s telephone line coupled to the jack. Although the configuration of FIGS. 3 a  and  3   b  might cost slightly more to manufacture than the configuration of FIGS. 2 a  and  2   b  due to its more complex design, the configuration offers the advantage of increased ergonomics, simplification of use, and a high density of activity with reduced operator impact time—thereby making it especially attractive for high density, high use network interface devices. 
     While there have been described what are considered to be preferred embodiments of the present invention, it will be readily appreciated by those skilled in the art that modifications can be made without departing from the scope of the teachings herein which analysis has shown can easily lead to upwards of a 50 percent reduction in the manufacturing cost of the modular jack, and can result in up to a 75% reduction in time spent in testing—both of which lead to significant cost savings in installation and use. For at least such reason, therefore, resort should be had to the claims appended hereto for a true understanding of the scope of the invention, in its use of a cover integral with the housing for capturing the cover so that it cannot be lost during testing by the field technician, and of fabricating both the cover and the housing of the same thermal coefficient of expansion so as to prevent any loosening with temperature cycling.