This invention relates to the general field of electrical connectors and is particularly concerned with outdoor mast lighting systems.
Mast lighting systems are well known and commonly support a light above the surface to be lighted with a long pole or mast. Masts are typically hollow, and may be round, square or of any selected cross-sectional shape which provides adequate stability. The mast may include a breakaway base at its lower end having an opening (or “handhole”) therein, through which the interior of the mast may be accessed by maintenance or installation personnel. The mast is typically mounted on a foundation of concrete or other suitable material set permanently into the ground and may be affixed to the foundation by a plurality of anchor bolts set into the foundation, which engage corresponding holes in the breakaway base.
Suspended at the top of the mast is an electrical component, commonly an electric light. In some applications, a cantilevered secondary mast or arm supports the light over a street or sidewalk. In other applications, a ring of high-intensity lamps may be supported radially around the distal end of the mast. The electrical component is electrically connected to a power source, generally in series with a number of other commonly powered mast units in a given area.
Power delivery to each light in a commonly powered system has been accomplished in a variety of ways. In one such system, the output of a master circuit breaker may be connected to an electric power cable which runs to the base of the mast. The power cable may connect to a fuse and surge arrestor assembly disposed within the hollow mast, which prevents current surges caused by lightning, voltage spikes or other anomalies from damaging the light fixture or the master circuit breaker. Access to the fuse and surge arrestor assembly is commonly provided by locating that assembly adjacent a handhole in the mast.
The performance of such a system is impaired by several shortcomings. Wire and cable attachments are generally made by splices, which are vulnerable to failure when tensile forces are applied to the connections.
In the event of an impact, the mast is often sheared off at the base and commonly comes to rest several yards from its original position. As is evident, the electrical circuit within the mast must be provided with means of disconnect which will allow the load side to separate from the line side by means of suitable tension applied to the load side conductors in the event a mast knockdown were to occur due to impact from a vehicle, thus preventing the feeder circuit being unearthed or broken; disrupting power to the rest of the circuit, which would be very important in the event of a nighttime accident; leaving broken or frayed electrical conductors exposed providing potential for electrocution to persons at the accident site; and energized electrical wires falling into traffic or the accident vehicle(s). In addition to these features, a fuse should be provided for protection of the load circuit, and in the event of a problem in the load circuit, the fuse would open, leaving the remainder of the lighting circuit energized.
Of particular importance, since this type of connector must be accessible for maintenance, is that the fuse be installed in such a manner that maintenance personnel are at no risk of electrical shock during fuse inspection or replacement. A further requirement for this application is that the connector be watertight, as certain conditions could occur, causing the connector to be submersed in flood water. Further, the connector should be easily assembled and serviced by technicians and capable of being capped on-site in the event of a mast knockdown.
These and other shortcomings in the prior art have been addressed by one or more embodiments of this invention which includes an electrical connector which will separate safely upon impact or tension of the adjoining wired connections. In various embodiments, the connector may be fused or unfused depending upon the particular application.
Roadway lighting masts or poles are mandated to breakaway at the base during impact. This type of light pole also requires an inline breakaway connector to be installed. This invention in various embodiments is such an inline breakaway connector which may be used in such settings. Additionally, fusing these connectors helps prevent any unintended electrocution. It is estimated that of the approximately 60 million street lights in the U.S.A., 26 million are roadway lighting and subject to breakaway regulations.
Connectors according to this invention may also be utilized for roadway lighting, parking lighting, electric vehicle charging stations, solar installations, traffic signals, lighted signage, LED conversion, sports lighting, and marine lighting to name just a few non-limiting examples.
The breakaway connector according to various embodiments of this invention may be utilized without allowing for voltage exposure. In various embodiments, mechanical screws are used to lock a fuse in place to the load side of the connector thereby providing a safer connection than with many prior art breakaway connectors. This invention also is easier to install because it includes fewer parts and therefore takes less time and space for installation. Moreover, it also minimizes the chance of incorrect installation. Conductors or stranded wires are inserted into the connector for easier installation and assembly. Various embodiments of this invention are also water resistant or waterproof.
Various embodiments of the connector according to this invention include caps which could be used to seal or isolate voltage and prevent inadvertent electrocution after a light pole impact or separation. The caps may be tethered to the entry points for the conductors and after impact, the cap may be removed and placed on the line side open to a voltage exposure. The same cap may also be used for sealing set screw access to the connector.
According to various embodiments, the connector of this invention utilizes two independent components which have modular design with the ability to be configured into six or more different products. This allows the connector to be converted in the field should regulations change from a non-breakaway device to a breakaway device with the addition of only one or a minimal number of parts. This connector may be utilized underground or in a submersible environment, allows for range taking and breakaway operation and may include a fuse, if appropriate. This connector may be manufactured from high-strength, 6061-T6 aluminum alloy and be rated for boo volts as well as certified for direct burial in earth or concrete and submersion applications and meet or exceed UL486A, B, D and ANSI 119.1 and 119.4 specifications.
These and other aspects of various embodiments of this invention overcome the shortcomings of the prior art and are shown in more detail in the accompanying drawings and following detailed description.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with a general description of the invention given above, and the detailed description given below, serve to explain the invention.
Referring first to
The mast 12 is rigidly attached to the pedestal 20 by welding, by a plurality of anchor bolts, or other standard connections. The mast 12 is commonly constructed of tubular aluminum, but may be of any suitable material, including concrete, steel or fiberglass. The mast 12 may also be of any selected cross section, including circular or square. The mast 12 is capable of supporting an electrical component 30. The electrical component 30 may be a standard street lamp 32, a high-watt high mast lighting system (not shown), or other desired device. An electrical cable 34 connects the electrical component 30 to a distribution component assembly 36. The electrical cable 34 is preferably sized for standard mast height and runs the length of the mast 12 through its hollow interior. Other embodiments of the electrical cable may be utilized, including commercially available mast lighting cables (not shown), or even a simple 3 wire cable having 14 gauge conductors (not shown).
The distribution component assembly 36 may be located within a chamber 38. Location of the distribution component assembly 36 within the chamber 38 may provide optimal protection from side impact damage due to traffic accidents or other collisions.
In one embodiment, the central conduit 22 may be constructed of pressure treated cylindrical PVC tubing or galvanized rigid steel piping of 6″ diameter. In this embodiment, the central conduit 22 may have an access hole 40 there through to allow passage of the incoming and outgoing feeder wires 24, 26 into the chamber 38. The foundation 14 may form the lower boundary of the chamber 38. Horizontal rebar (not shown) may be provided extending into the surrounding pedestal 20 for securing the central conduit 22 after the concrete sets.
The distribution component assembly 36 may include, in one embodiment, a surge arrestor and one or more electrical connectors 44 (see
The mast 12, near the proximate end 35 which may be above the foundation 14, defines an opening or handhole 42, through which the chamber 38 is accessible by the user. The handhole 42 may extend through the main body 72 of the mast 12 itself, or through a breakaway cover 46 on the mast 12 at its proximate end 35. The location of the opening or handhole 42 should be near enough to the foundation 14 and chamber 38 therein that the distribution component assembly 36 is accessible by hand to maintenance or installation personnel, thereby simplifying routine maintenance and repair to be performed on the mast lighting system 10. The handhole 42 may be covered between repairs or maintenance by the cover or door 46.
In one embodiment, the electrical connector 44 in the assembly 36 between the feed wires 24, 26 and the electrical cable 34 is a watertight breakaway connector. The breakaway connector 44 preferably disengages under tension, such as when a mast 12 fails due to vehicular impact. In any event, the tensile force required to disengage the breakaway connector 44 is less than the tensile force necessary to damage the electrical cable 34 or electrical connections thereto. When the breakaway connector is properly mated and locked, it preferably forms an enclosure which meets the local municipal and other requirements.
Referring to
Each metal body 48 includes a conductor receiving bore 50 extending longitudinally into the metal body 48 on one end thereof. Each conductor receiving bore 50 is adapted to receive a stranded conductor or other wire. The stranded conductor may be the incoming feed wire 24 or the electrical cable 34 and if it is a stranded conductor comprises a compacted bundle of individual strands of an electrically-conducted material such as copper or aluminum. Each conductor receiving bore 50 is generally cylindrical and has a circular cross section of a radial dimension adequate to receive the conductor therein. Each conductor receiving bore 50 is disposed substantially orthogonally to the planes defined by the sidewalls of the metal body 48.
A threaded bore 52 extends downwardly through the top surface of each metal body 48 and communicates with the interior of the associated conductor receiving bore 50. A longitudinal axis of the threaded bore 52 is disposed substantially orthogonal to a longitudinal axis of the conductor receiving bore 50. The threaded bore 52 includes a continuous helical thread 54 disposed along a substantial portion of the interior surface of the bore 52. Each threaded bore 52a, 52b receives therein a binding fastener such as a binding screw 56 removably received within the threaded bore 52. Each binding screw 56 may include a generally conical tip 58 having a slightly blunted extremity of a small radius of curvature and an inclined surface 60 relative to the plane tangent to the blunted extremity so that the contacting strands of the stranded conductor will be induced to slidably deflect there along. In addition, the conical tip 58 encourages strands to rub together and remove oxidation from the surfaces thereof so that the quality of the electrical connection is improved.
To facilitate insertion into the threaded bore and subsequent tightening, the binding screw 56 has a shaped recess 62 for receiving a corresponding-shaped tool (not shown). Recess 62 and tool removably receivable therein may have a hex-type or Allen-type connection. Other configurations of binding screw 56 are possible such as a binding screw having a slotted head or a Phillips-type head which can be tightened with an ordinary screwdriver.
Each metal body 48 may be formed by extrusion or any other known method of metal fabrication. Each metal body 48 may be composed of an aluminum alloy and, for the sake of compatibility during thermal cycling, the binding screw 56 and the electrical connector 44 may be composed of similar aluminum alloys.
As shown in
A fuse clip receiving bore 70 is formed in the line side metal body 48b extending longitudinally from an end of the metal body 48b opposite from the conductor receiving bore Sob therein. A threaded bore 52d likewise extends downwardly through the top surface of the line side metal body 48b and communicates with the interior of the fuse clip receiving bore 70. A longitudinal axis of the threaded bore 52d is disposed substantially orthogonal to the longitudinal axis of the fuse clip receiving bore 70 and includes a continuous helical thread 54 disposed along a substantial portion of the interior surface thereof. A binding screw 56 is removably received within the threaded bore 52d. The binding screw 56 and fuse clip receiving bore 70 are adapted to selectively secure a fuse clip 72 in the fuse clip receiving bore 70 such that the fuse clip 72 extends longitudinally from the end of the line side metal body 48b as shown in
Each of the metal bodies 48 may be encased in plastic, rubber or other protective and non-conducting coating 78 substantially enveloping the metal body 48 on all sides. The insulating cover may be of any color and in various embodiments is black or clear plastic. The coating 78 may be polyvinyl chloride and include passages 80 for receiving the conductors, binding screws, fuse and fuse clip components of the electrical connector 44 according to various embodiments of this invention. The passages Boa of the cover 78 are formed upwardly extending from the top face of the metal body 48 and aligned with the threaded bores 52 for the binding screws 56 to pass there through and into the threaded bores 52. The passages Bob on the longitudinal ends of the metal bodies 48 allow for the passage of the conductors into the conductor receiving bores 50. Passages 80c, Sod are for the fuse receiving bore 64 and the fuse clip receiving bore 70 as shown generally in
The shape, design and configuration of the passages 80c, 80d associated with the fuse receiving bore 64 and fuse clip receiving bore 70 on the compatible metal bodies 48a, 48b are intended for mating the metal bodies together as shown generally in
Referring to
A further alternative embodiment of the connector 44 according to this invention is shown in
Use of a breakaway connector 44 in the mast lighting system 10 prevents broken wires and de-energization of a complete circuit when one component such as a mast 12 fails. The breakaway connector 44 separates safely under tension, eliminating danger and electrical shock. When it comes time to replace a failed mast 12, the existing electrical cable 34 can be re-used or replaced without replacing the underground feeder wires 24, 26 distribution component assembly 36 or the breakaway connector 44. A breakaway connector 44, which is rated for 15 amps, 480 volts, and which safely disengages under a tension of 7.5 lb may be employed. The connector 44 may disengage at the fuse juncture and/or at either or both conductor junctures.
While this invention has been illustrated by the description of one or more embodiments thereof, and while the embodiments have been described in considerable detail, they are not intended to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and method and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the scope or spirit of the general inventive concept.
This claims the benefit of U.S. Provisional Patent Application Ser. No. 62/101,412, filed Jan. 9, 2015 and hereby incorporated by reference in its entirety.
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Number | Date | Country | |
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Number | Date | Country | |
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62101412 | Jan 2015 | US |