Telephonic communications – Subscriber line or transmission line interface – Network interface device
Reexamination Certificate
2000-01-21
2003-01-21
Chiang, Jack (Department: 2642)
Telephonic communications
Subscriber line or transmission line interface
Network interface device
Reexamination Certificate
active
06510226
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an improved network housing device, and more particularly, to an improved device for protecting communications and electrical systems disposed in the outdoors from foreign objects and degradation from weathering.
BACKGROUND OF THE INVENTION
Cables, wires, and circuit boards of communications and electrical products at times must be mounted in the outdoors, for example, on the exterior of a plant house, or other building. Traditionally, metal housings such as network interface units have been used to encase the equipment in these settings to protect them from weathering, ie., degradation from moisture, temperature changes, ultra-violet rays of the sun, atmospheric contaminants, and so forth. (For ease of reference, the term “network” is used to collectively refer to all types of cables, wires, or circuit boards of communications, electrical, or optical products and also encompasses parts of such systems including wireless systems).
Metal enclosures predominantly have been used for these applications because metal is highly reliable, that is, it maintains its structural integrity over long periods of time and provides excellent protection against foreign matter and environmental influences, such as damaging ultra-violet rays. A metal housing device for outdoor mounting is described, for example, in U.S. Pat. No. 5,550,916 issued Aug. 27, 1996, to Daoud, titled “Telecommunications Equipment Terminal,” and assigned to Lucent Technologies, Inc., (the.assignee herein), which is hereby incorporated by reference. As discussed in the Daoud '916 patent, it is difficult to provide sufficient protection for these units from the outdoor elements. Reliability and structural integrity is a significant concern for the housing devices as defects in the housing could cause disruption in electrical or telecommunications service, having a drastic and unacceptable impact on the daily lives, responsibilities, or conveniences of the users.
While metal enclosures demonstrate high reliability, there are drawbacks associated with their use, particularly as relates to cost. Metal housings are more expensive than plastic housings, and they often require hinges, gasketing, and rubber sealing materials which further increase the complexity of the housing and cost. The impact of the increased cost of metal as compared with plastic becomes more dramatic as the volume of the number deployed increases. Metal also is less flexible and heavier than plastic, limiting device configurations and installation parameters.
However, plastic enclosures have been considered unsuitable for outdoor housing units for protecting electronics due primarily to reliability constraints. Challenges have been encountered in developing plastic network housings that meet the stringent requirements dictated by outdoor use, such as good chemical resistance, flame retardance, effective radio-frequency (RF) shielding, and maintenance of structural integrity and stability in the face of weather and ultra-violet ray influences over a long operating life and large range of temperatures (i.e., −40° C. to 70° C.). Generally, available polymers can be used to produce a housing that will meet some, but not all, of these requirements. For example, with present device configurations and using currently available polymers, a housing could be fabricated having good fire resistance properties, but the same housing may not exhibit ultra-violet stability or meet all other requirements dictated by outdoor use.
Previous housing units are shown in U.S. Pat. No. 5,537,456 to Bonvallat et al. and U.S. Pat. No. 4,910,770 to Collins. These designs exhibit drawbacks as applied to the outdoor mounting of telecommunications equipment. For example, the Collins patent states that its device is adapted for indoor use or for use in situations where complete isolation of the subscriber and telephone company terminals is not required (col. 2, l. 49-52). The Collins patent calls for a “Dutch door” arrangement, wherein two covers are hinged onto the rear base of the unit. Equipment is secured adjacent the rear wall of the unit (e.g., FIGS. 11 and 19), and thus, is not isolated or insulated from outdoor influences. The covers are designed to provide security for telephone terminals which themselves are weather protected (e.g., col. 2, l. 49-50). For example, Collins states the user can gain access to the equipment behind cover 3 by “unfastening screw 15 disposed in tab 17 of cover 3 . . . ” (Col. 5, l. 50-52). FIG. 3 of Collins shows access holes 27, 29 in the base of the unit, and FIG. 6 shows the equipment disposed within the unit, below cover 3, adjacent access holes 27, 29. There is no barrier between the equipment and the rear wall 1a of the base, and thus, no protection from outdoor influences. Similarly, FIGS. 7 and 8 of Collins show the equipment housed within the unit, against the rear wall 1a of the base, adjacent access holes 27, 29. Likewise, in the Bonvallat design, components are mounted adjacent the rear wall of the unit and/or adjacent the top face wall of the unit (e.g., FIG. 3), and thus, there is little protection from outdoor influences.
Accordingly, there is a need for an improved network housing device. The invention addresses these needs by providing a housing having a structure which allows for use of plastic in fabrication and which may be used to protect printed circuit boards of telecommunications equipment from outdoor influences, overcoming previously-mentioned limitations. Further advantages may appear more fully upon considering the description below.
SUMMARY OF THE INVENTION
Summarily described, the invention embraces a dual enclosure device for housing telecommunications or electrical equipment in the outdoors comprising at least an outer enclosure unit and an inner enclosure unit. The inner enclosure unit encases the telecommunications or electrical equipment and is fabricated from a material exhibiting flame retardance properties, and the outer enclosure unit encases the inner enclosure unit and is fabricated from a material exhibiting resistance to weathering. In one embodiment, the outer enclosure unit comprises two parts, a face portion (or external cover) and a rear portion (or shroud), and the inner enclosure unit comprises three parts, a base plate for providing a central structural unit, an internal cover for protecting the circuit board of the network, and an access door for providing an accessible cover over field serviceable components. Advantageously all parts are fabricated with plastic and are fastened together with use of plastic attachments, with all internal areas accessible through hinged doors and the mating surfaces sealed with a tongue and groove seal.
REFERENCES:
patent: 4910770 (1990-03-01), Collins et al.
patent: 5363440 (1994-11-01), Daoud
patent: 6078661 (2000-06-01), Arnett et al.
Thomann Brian J.
Zimmerman Michael A.
Chiang Jack
Lowenstein Sandler P.C.
LandOfFree
Dual network housing device does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Dual network housing device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Dual network housing device will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3063438