Mast-type outdoor lighting system

Abstract

An improved outdoor lighting system is provided that comprises a light assembly formed from at least one tubular mast having a distal end for supporting an electrically powered light source, and a proximal end mounted in the ground, and an electrical cable for connecting the light source to an underground power source. The improved system includes an electrical connector assembly in the cable located in the vicinity of the ground-mounted distal end of the tubular mast. The electrical connector assembly spontaneously disconnects in response to an application of an tensile force indicative of an automobile collision with the mast, thereby preventing damaging tensile forces from being transmitted along the underground portion of the cable to the circuit breaker. The system further comprises an underground fuse assembly and lightning arrestor, both of which are mounted in an underground box electrically connected between the circuit breaker, and the underground portion of the cable that terminates in the aforementioned connector assembly. The remote, underground location of the fuse assembly and lightning arrestor provides easy and safe access to these components by maintenance personnel while discouraging vandals from tampering with or stealing these components.

Description

[0001]This reissue application of U.S. Pat. No. 5,335,160 was merged with reexamination application Nos. 90 / 005,715; 90 / 005,719 and 90 / 006,130 previously filed on Apr. 28, 2000, May 4, 2000 and Oct. 16, 2001, respectively, and is the parent of continuation reissue application No. 10 / 960,901 filed Oct. 8, 2004.BACKGROUND OF THE INVENTION[0002]This invention generally relates to outdoor lighting systems for illuminating highways or airports and the like, and is specifically concerned with an improved system of the type wherein outdoor lights are mounted on a plurality of spaced-apart tubular masts and powered by a common, underground circuit breaker.[0003]Outdoor lighting systems for illuminating streets and highways are known in the prior art. Such lighting systems typically include a plurality of lighting units spaced along the road or highway, each of which includes an electric light that is supported on the distal end of a tubular mast whose proximal end is anchored into the groun...

AI Technical Summary

Benefits of technology

[0009]The invention is an improved outdoor lighting system of the type including at least one lighting assembly having a tubular mast, and an electrical cable extending through the mast and underground for connecting a light source located at a distal end of the mast to a circuit breaker that overcomes or ameliorates all of the aforementioned shortcomings associated with prior art outdoor lighting systems. The invention comprises an electrical connector assembly in the electrical cable near the proximal, ground-mounted end of the tubular mast for spontaneously disconnecting the cable at that location upon the application of a tensile force indicative of a vehicle collision with the mast. In the preferred embodiment, the electrical connector assembly includes first and second matable connectors which spontaneously disconnect upon the application of a tensile force much less than that which would damage the connection between the electrical cable and the underground circuit breaker (or other source of power) such as, for example, a force of between 20 and 30 pounds. The first and second matable connectors each include means for isolating the conductive pins and barrels contained in each from ambient water to prevent corrosion of the metals forming the conductive pins and barrels.

[0011]Finally, the improved system may include a lightning arrestor mounted in the same box that contains the fuse assembly. The lightning arrestor includes a surge suppressor circuit which is connected to a ground rod which extends outside the surrounding box. Preferably, the junction box that forms part of the fuse assembly also functions to electrically connect the cable leading from the light source to the surge suppressor circuit of the lightning arrestor, as well as to the power cable of an adjacent lighting unit. A third electrical connector may be provided in the cable between the junction box and the surge suppressor circuit so that the surge suppressor circuit may be easily replaced if burned out as a result of lightning striking the light source connected to the mast.

[0013]Both the improved system and the method of the invention results in an outdoor lighting system that is far safer in the event of an automobile collision with one of the masts of the systems, since the forces associated with the collision will only cause the electrical connector assembly at the proximal end of the mast to spontaneously disconnect without exposing any dangerous wires, and without transmitting any potentially damaging tensile forces to other cables and connectors of the system. Locating the fuse assembly and lightning arrestor in an underground box, instead of within the hollow base of the mast, discourages vandals from stealing or damaging these components while freely allowing maintenance personnel with the proper tools to safely access these components without disturbing potentially hostile wildlife.

Problems solved by technology

Additionally, the wrenching tensile forces applied throughout the length of the cable just before the breakage thereof at the fuse assembly splices often weakens splices and other connections made with adjacent lighting units, setting the stage for future maintenance problems that are difficult to diagnose and solve.

While such prior art lighting system are widely used to illuminate streets, highways, and virtually any place where large amounts of outdoor lighting is required, the applicant has observed a number of shortcomings associated with the design of these systems which significantly impairs their overall usefulness.

For example, if one of the masts of such a system should be knocked down as a result of an automobile collision, the stresses applied to the cable within the mast often causes it to break at the connections made with the fuse assembly.

As these connections are typically made by way of splices, the tension applied to the cable from the automobile collision tears the splices apart, dangerously exposing wires that are “hot”.

These exposed, hot wires can in turn conduct dangerous electrical currents through the knocked-down mast (which is typically made of a conductive metal) or even the body of the colliding car.

Even if the collision causes the exposed conductors of the broken cable splice to short circuit and trip the circuit breaker, this somewhat safer result is not particularly desirable, as such tripping will cut off the current flowing to all of the other mast-supported lights that are serially connected to the breaker, thus surrounding the area around the broken mast in total darkness if the collision occurs at night.

Additionally, the wrenching tensile forces applied throughout the length of the cable just before the breakage thereof at the fuse assembly splices often weakens splices and other connections made with adjacent lighting units, setting the stage for future maintenance problems that are difficult to diagnose and solve.

Because such masts usually have openings at their upper ends or sides for structural reasons, the interior of such masts often becomes the home of wildlife that is either potentially hostile (such as wasps, poisonous snakes, or rats) or of the type apt to build nests around these components (such as birds or squirrels).

The presence of such animal life significantly impairs the replacement of fuses of burned-out lightning arrestors by either assaulting the maintenance personnel who carry out such operations, or by creating physical obstructions (such as nests) that must be removed incident to such operations.

Additionally, the spliced connection between the lightning arrestor and the cable that supplies electrical power to the light source makes it difficult to replace this component in the event of a burn out of the surge arrestor circuit in the arrestor from a bolt of lightning striking the conductive mast.

The present access panels are easily opened by vandals who may tamper with or destroy the components inside, or by thieves who attach the cable leading to the circuit breaker to a truck and pull it out of the ground for the purpose of selling the relatively large amounts of copper in it.

In recent years, such vandalism and theft has been a major drain on the maintenance budgets for such lighting system in both the public and the private sectors of the economy.

Such a system should further make is difficult, if not impossible, for vandals or thieves to destroy or steal large lengths of heavy copper cables or other valuable components located inside the masts.

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