Abstract:
A support assembly capable of being raised and lowered on a mast and configured in a compact, volumetrically efficient conformation lending architectural significance to the appearance of the support assembly when used to mount a plurality of luminaires or other apparatus intended for use in a location above a surface, such as the surface of the earth, the invention permits remote latching and unlatching of the support assembly through use of an improved latching mechanism having dimensions permitting housing of the latching mechanism within an enclosure of a reduced height, thereby lending an esthetically pleasing appearance to a mast-mounted support arrangement relative to prior art assemblies intended to perform similar functions.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The invention relates generally to mechanisms employed to raise and lower groupings of luminaires or other apparatus mounted to a support assembly and positionable at or near a distal end of a mast such as a high mast as is useful for illumination of a roadway or the like, the invention particularly relating to a latching mechanism of compact conformation permitting configuration of a relatively low profile support assembly having improved operation and esthetic appeal. 
   2. Description of the Prior Art 
   Clusters of luminaires intended for outdoor illumination have long been mounted to a support ring capable of being hoisted to or near the top of a “high mast”, typically through use of a winch and associated hoisting cables, the support ring being readily lowered for necessary maintenance, repair or replacement of the luminaires. In certain applications, devices other than luminaires are mountable by a support ring for raising/lowering of the resulting assembly along a high mast, reference herein to luminaires so mounted encompassing such other devices. In accomplishment of the functions so noted, the support ring carrying the luminaires must be mounted for movement along the mast between a lowermost or ground-level position necessary for servicing and the like and an operational uppermost position at or near the top of the mast at which the luminaire-bearing support ring is releasably yet positively latched to a stationary support permanently located at an upper portion of the mast. Latching mechanisms typically employed for accomplishing such functions include a latch pin carried by the support ring, such latch pins engaging latch barrels mounted to the stationary support permanently mounted at the top of the mast. Mating of a number of the latch pins with a corresponding number of the latch barrels on completion of the hoisting operation results in positive engagement between the latch pins and the latch barrels sufficient to latch the support ring to the stationary support until disengagement to allow the luminaire-bearing support ring to be lowered back to the ground as desired. Latch barrels such as are common in the prior art are mounted substantially vertically with openings disposed downwardly to permit receipt of one each of the latch pins into said opening as the latch pins engage the latch barrels, the latch pins being necessarily oriented in a vertical sense in order to provide the desired function. Vertical orientation of the latch pins and latch barrels unavoidably cause the assembly resulting from the mating of the support ring and stationary support to be less than compact in “height”, thereby lending a bulky appearance to the resulting assembly. Prior high mast lighting systems, while functional mechanically and useful for accomplishment of intended operation, have not generally exhibited esthetic appeal due at least in part to an unavoidable height dimension relative to other dimensions of known support ring/stationary support assemblies. Further, mechanical sub-assemblies of prior art systems are typically exposed to view and are therefore lacking in esthetic appeal. An architecturally appealing high mast hoisting system could be realized by the ability to reduce the height of such assemblies along with the ability to cleanly mate the support ring with the stationary support so that the assembly appears as an essentially unitary enclosure or housing from which luminaire-mounting arms cleanly and attractively extend for mounting of luminaires or the like. Attainment of an architecturally appealing structure at reduced cost lends increased improvement over the prior art, such cost reduction being realized in part by elimination of costly and bulky latch barrels. Such bulky latch barrels, when exposed to view, are lacking in esthetic appeal. Prior art difficulties associated with jamming of latch pins with camming surfaces disposed within the interior of latch barrels would preferably be avoided by improved latch pin structure having cam-following pins positively engageable with such camming surfaces without the tendency to “cock” or tilt with resultant jamming. 
   The prior art is replete with systems proposed for use and which are actually used for raising and lowering luminaire assemblies along high mast poles, such prior systems being deficient in esthetic appeal as alluded to hereinabove. Typical prior art systems include that system described by Murray et al in U.S. Pat. No. 4,234,165, in which a circular support ring carrying luminaires is hoisted along a high mast pole to an operational position adjacent a cylindrical housing disposed atop the pole, the housing covering a stationary support. The support ring simply abuts the housing and is not esthetically pleasing in appearance. Luminaires carried by a support ring are raised and lowered according to the teachings of Garchinsky in U.S. Pat. No. 4,228,488, the support ring abutting a housing covering a stationary support mounted atop a high mast pole on completion of the raising function, the result being less than esthetically pleasing. Latimer, in U.S. Pat. No. 5,975,726 discloses a high mast lighting system comprised of a luminaire-bearing annular support ring which fails to visually integrate with a covering housing fixed atop a high mast pole on hoisting of the support ring to an operational position adjacent the housing. Blahut, in U.S. Pat. No. 4,115,845, fails to provide a high mast system with visual appeal. Garchinsky, in U.S. Pat. Nos. 4,149,230 and 4,429,355 discloses high mast assemblies of conventional appearance. The appearance of the high mast systems disclosed by Richter in U.S. Pat. No. 6,261,122 and Thompson in U.S. Pat. No. 4,139,884 is essentially less than pleasing as are the systems disclosed by Staniec in U.S. Pat. No. 6,074,075; Hunt et al in U.S. Pat. No. 3,633,980; Savoca in U.S. Pat. No. 5,718,602; Richter in U.S. Pat. No. 6,261,122 and Thompson in U.S. Pat. No. 4,348,717 inter alia. 
   The art has experienced a long-felt need for a high mast hoisting system having architectural esthetics as well as a favorable cost profile. The present high mast system addresses such needs by providing a luminaire-bearing support ring of a shape and dimensions permitted in part by a low profile latching mechanism that further permits economies of cost in the construction of a system used in environments within which the invention is intended. 
   SUMMARY OF THE INVENTION 
   The invention provides architecturally significant and visually esthetic apparatus such as finds utility in high mast use environments wherein luminaires and the like are mounted in clusters to a support structure movable along a vertical pole between a lowermost position and an operational position at or near a distal end of the pole. A luminaire support base movable along the pole by means of a conventional winch and cable arrangement is raised into adjacent relation to a stationary support housing fixed to the pole at or near the distal end of the pole. The support base releasably and positively latches to the stationary support housing by means of at least one low profile latching mechanism, a portion of the latching mechanism including a cam-following pin slidable within a pin housing carried by the movable support base while a cam plate having camming surfaces formed therein. The pin engages the camming surfaces and slides within the pin housing to assume a position whereby the support base latches to the support housing in a contiguous relationship whereby the support base visually integrates with the support housing to provide an esthetically pleasing appearance. 
   The latching mechanism of the invention is configured in a compact, volumetrically efficient conformation having a particularly low profile in the height dimension, this height dimension being reduced relative to prior art latching mechanisms thereby permitting an assembly formed of the support base and the support housing to be of a reduced height relative to the height for “thickness” of prior art assemblies. The reduced profile of the present assembly formed of the support base and support housing lends a more esthetically pleasing appearance to the present assembly and permits in part design of an architecturally desirable high mast system. The present latching mechanism is also less costly to fabricate while exhibiting improved operational capability, the structure of the present latching mechanism being less likely to jam during latching and unlatching operation than at least certain prior art latching mechanisms used in high mast applications. The present latching mechanism therefore constitutes improvement in the art by virtue of high reliability and low cost as well as by virtue of compact low profile conformation permitting configuration of an esthetically pleasing architecturally significant high mast system. The support base and the housing support are preferably conformed as rectangular solids, particular square in lateral section, with the support base fitting against or slightly into the housing support to provide a stepped appearance. The compact, low-profile configuration of the support base and housing support combination also offers less resistance to wind forces, thereby permitting use of a less substantial pole for a given wind speed rating. 
   The high mast system of the invention also provides a centering mechanism capable of maintaining coaxial alignment of a luminaire-bearing support base on a pole as said support base is moved along the pole. The centering mechanism comprises a plurality of centering arms disposed at intervals about and mounted to the support base, each of the centering arms being resiliently mounted for pivoting movement so that each arm biases a roller against the pole to maintain the support base in a substantially centered position relative to the pole and to avoid shock to luminaires mounted by the support base. Each centering arm is biased against the pole by means of a spring-loaded piston arm mounted within a cylinder mounted at one end to the support base and at the other end to the centering arm between that end of the arm on which the roller is mounted and the end of the arm mounted to the support base. While a centering mechanism as explicitly disclosed herein is preferred, it is to be understood that centering mechanisms of other configurations including prior art centering mechanisms can be employed. 
   The present high mast system further provides a ballast housing whereby a remote ballast is mounted directly to a pivotably mounted housing door such that access to the ballast is readily gained by opening of the door. The housing door can be opened rapidly due to secure mounting of the door in place without the use of fasteners such as screws. 
   Accordingly, it is an object of the invention to provide apparatus for moving along a pole a support base bearing at least one luminaire or the like such as in a high mast lighting system for illuminating roadways and the like, the apparatus being configured to provide an esthetically pleasing appearance of architectural character, the support base being positionable on the pole in relation to a stationary support housing fixed permanently at or near the top of the pole and being dimensioned compactly to permit a low profile appearance having visual appeal. 
   It is another object of the invention to provide a latching mechanism for releasably latching a support base bearing at least one luminaire or the like to a housing support fixed atop a pole, the support base being moved along the pole to a position whereby the support base is latched to the housing support or associated structure mounted to the pole, the latching mechanism being low cost in manufacture with a high degree of operational reliability, the latching mechanism further being sufficiently compact as to permit a height-wise dimensional reduction such that the latched together combination of the support base and the housing support has a visually pleasing, relatively reduced profile. 
   It is a further object of the invention to provide a support base and a housing support for a high mast lighting system, the support base and the housing support being box-like in conformation and particularly square in lateral section, the support base bearing at least one luminaire or the like and being movable along a pole to latch to the housing support, the support base fitting against or slightly into the housing support to provide a stepped appearance on latching of the support base to the housing support. 
   Further objects and advantages of the invention will become more readily apparent in light of the following description of the preferred embodiments of the invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a high mast lighting system illustrating architectural detail of the system; 
       FIG. 2  is an exploded view in perspective of the high mast lighting system of  FIG. 1  illustrating the location of a support base disposed along a pole to which a housing support is permanently mounted atop the pole, the support base being spaced from the housing support in an unlatched condition; 
       FIG. 3A  is a top view of the support base illustrating operational mechanisms contained within the support base; 
       FIG. 3B  is an elevational view in section taken through the support base latched to the housing support; 
       FIGS. 3C and 3D  are detail views of a preferred latching mechanism; 
       FIGS. 4A through 4C  are detail views of the latching mechanism of the invention; and, 
       FIG. 5  is a detail view of a ballast housing. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The disclosures of U.S. Pat. Nos. 3,633,980; 3,721,816; 3,847,333; 4,115,845; 4,139,884; 4,149,230; 4,228,488; 4,234,165; 4,348,717; 4,429,355; 4,661,894; 5,718,602; 5,975,726; 6,074,075 and 6,261,122 are incorporated hereinto by reference. 
   Referring now to the drawings and particularly to  FIGS. 1 and 2 , a high mast system is shown generally at  10  to be operable on a pole  12 , the system  10  having an esthetically pleasing appearance due in part to an architectural “feel” evidenced by a stepped juxtaposition of a movable support base  14  with a fixed housing support  16 , upper edges of the support base  14  being disposed either immediately adjacent to lower edges of the housing system  16  or slightly inside of said housing support  16 . The architectural feel is provided in part by formation of the housing support  16  with greater dimensions permitting a fitting of the support base  14  slightly into an open lower face of the housing support  16  where desired. Whether or not the support base  14  extends slightly into the housing support  16  or is merely raised into adjacent and flush relationship therewith, a stepped appearance results. 
   Architectural character is also provided by formation of the support base  14  and the housing support  16  as square “boxes” or rectangular solids geometrically, the support base  14  being capable of configuration with a low profile due at least in part to the configuration of latching mechanisms that require less vertical height than is required when latch pin/latch barrel arrangements are used as is common in the prior art. A compact visual character results on latching of the support base  14  to the housing support  16 , the system  10  having substantial visual appeal when compared to prior, more bulky high mast systems. 
   The support base  14  has at least one support arm  18  extending from at least certain of lateral surfaces  20 , each support arm  18  terminating in a luminaire  22 . Luminaires of varying conformation can be employed in a usual practice of the invention. Further, devices other than luminaires can be mounted to the support arms  18 . As will be apparent to those familiar with the art, any reasonable number of luminaires can be mounted to the support base  14  including a single luminaire  22  (not shown). The support arms  18  are preferably formed as enclosed and extended channels or rectangular solids rather than the cylindrical arms often used in conventional high mast systems, the shape of the present support arms  18  lending additional architectural character to the system  10 . 
   The structural elements so disclosed are preferably formed of metal such as stainless steel, polyester powder coated steel, aluminum, etc. Poles useful with the invention are as is commonly used in the art and include round tapered, square tapered, round straight or square straight poles. Pole heights can vary as is common in the high mast art, raising and lowering systems being necessary in applications wherein a luminaire cluster must be raised to an operational position and lowered to a repair or maintenance position. Pole heights are typically on the order of ninety feet or even greater. Luminaire-bearing support rings are typically raised and lowered on poles by means of winch/power apparatus that operate a cable system as is common in the art. Such apparatus need not be described herein since the art is replete with apparatus suitable for such use, the winch/power apparatus and cable system used with the system  10  not being a part of the present invention. 
   The support base  14  and housing support  16  could be formed as cylinders dimensioned to provide a stepped appearance. However, the box-like rectangular solid conformation of the support base  14  and housing support  16  as illustrated herein provides a more pleasing appearance especially in combination with the shape of the support arms  18  as shown. 
   As is best seen in  FIG. 2 , the housing support  16  has a cover  24  disposed over a headframe  26 , the cover  24  being the only portion of the housing support  16  that is visible in use. The cover  24  is mounted over the headframe  26  and fixed removably thereto to provide a more esthetic appearance than would the headframe  26  if left uncovered. The headframe  26  is permanently mounted to the distal end of the pole  12 , the head frame  26  essentially having a cruciform configuration with arms  28  being conveniently formed of steel channels which, when assembled, provide a conformation similar to that of an I-beam. The headframe  26  mounts cable sheaves (not shown) and associated mechanisms necessary to raising or lowering of the support base  16 , such apparatus being substantially conventional in the art. 
   Two oppositely disposed arms  28  of the headframe  26  each respectively mount a cam latch plate  30  inwardly of distal ends of said arms  28 , a recessed camming pattern  32  being formed in an outwardly facing surface of each of the latch plates  30  as is best seen in  FIGS. 4A and 4B . The latch plates  30  are fixed in place on the headframe  26  and cooperate with structure disposed on the support base  14  to releasably latch the support base  14  to the headframe  26  and thus the housing support  16  as will be described in detail hereinafter. 
   The support base  14  is seen in  FIGS. 3A and 3B  inter alia to be formed of four channels  36  having inwardly turned edge flanges  38 , the channels preferably being fabricated of twelve gauge cold-rolled steel welded together at intersecting corners resulting in the formation of a box-like assembly typically sized to be approximately twenty-six inches on a side and approximately nine inches in height. Conventional angle and plate reinforcements as well as brackets are used to provide adequate strength. Various apertures and the like are formed in the channels  36  to permit cables (not shown) to engage the support base  14  in a conventional manner. One each of the support arms  18  extend from each outer face of each channel  36  in a preferred embodiment. 
   Referring also to  FIGS. 3C ,  3 Ds and  4 A through  4 C, a latch assembly  40  is seen to be mounted to two opposite channels  36 , the latch assembly  40  having a base plate  42  having side flanges  44  that cooperate with housing plate  46  to define a housing within which a slide plate  48  is free to move laterally between the housing plate  46  and a track plate  49  disposed between the base plate  42  and the housing plate  46 . The track plate  49  is spaced from the housing plate  46  a sufficient distance to allow free sliding movement of the slide plate  48  therebetween. As is best seen in  FIG. 4C , the housing plate  46  has a laterally extending slot  50  formed therein, a cam following pin  52  carried by the slide plate  48  extending through the slot  50  to engage the surfaces  34  of the recessed camming pattern  32  formed in the cam latch plate  30  on raising of the support base  14  along the pole  12 . The latch assembly  40  can be configured to operate within a vertical distance of lesser dimension than occurs with commonly available latching mechanisms used in high mast systems, that is, the low profile of the latch assembly  40  permits the support base  14  to have a height dimension that is less than corresponding structure of prior high mast systems. This compact conformation of the support base  14  in addition to the ability to similarly dimension the housing system  16  lends an esthetic appearance to the high mast system  10  in an operational configuration wherein the support base  14  is latched to the housing support  16 . 
   With continuing reference to  FIG. 4C  in particular, the base plate  42  of the latch assembly  40  is provided with angled guides  54  to facilitate reception of the cam latch plate  30  into functional relation with the latch assembly  40 . The camming pattern  32  is seen to be open along lower edge  56  as best seen in  FIGS. 4A and 4B  to permit receipt of the pin  52  into the recessed camming pattern  32  as the support base  14  is raised along the pole  12 . The pattern  32  has a shape similar to an upper case “R”, a pattern similar in shape to camming surfaces formed in walls of prior camming latch structures. As is shown in detail in  FIGS. 4A and 4B , the pin  52  initially follows an angled portion of the surfaces  34  to enter an arcuate inner portion of the pattern  32 , the pin  52  following the arcuate inner portion of the pattern to lodge against within a V-shaped groove of an interior détente  58  as the support base  14  is raised to the operational position relative to the housing support  16 . During the latching process, the pin  52  slides within the slot  50  as the slide plate  48  moves laterally of the latch assembly  40  on bias caused by motion of the support base  14 . 
   Unlatching of the support base  14  from the housing support  16  occurs by a further raising of the support base  14  relative to the housing support  16  to cause the pin  52  to move along the surfaces  34  of the camming pattern  32  toward a straight-sided portion  59  thereof to thereby permit the pin  52  to disengage from the cam latch plates  30  on lowering of the support base  14 . The support base  14  can then be lowered to ground level for repair, maintenance or replacement of luminaires or the like mounted to the support base  14 . 
   Referring now particularly to  FIGS. 3A and 3B , the support base  14  mounts interiorly thereof a centering mechanism  60  having a plurality of centering arms  62  each provided with a roller  64  disposed near the distal end of said arm. Preferably, four of the centering arms  62  are mounted one each to interior walls of each of the channels  36  and centrally of the length of each said channel. The centering arms  62  are each formed of an elongated steel rod bent medially of the length thereof and pivotally mounted at an outer end  76  to one of the corresponding channels  36 . A spring-loaded cylinder  66  is also mounted to each of the channels  36  with a piston rod  68  of each said cylinder  66  being pivotally connected to one each of the centering arms  62  at a location inwardly of the point of attachment of the centering arms  62  to the channel  36 , such connection not being expressly shown. The cylinder  66  functions to spring-load the centering arm  62  to bias a distal end of said centering arm inwardly toward the pole  12  to engage the roller  64  against the pole  12 . The roller  64  carried by each of the centering arms  62  remains in contact with the pole  12  during raising and lowering of the support base  14  whether the pole  12  is round, square, tapered or straight. 
   While the centering mechanism  60  shown in  FIGS. 3A and 3B  is preferred, it is to be understood that other centering mechanisms could be employed. Examples of suitable centering mechanisms are shown in certain of the patents incorporated hereinto by reference. 
   As is seen in  FIG. 5 , a ballast  70  necessary for operation of the luminaire  22  is mounted to door  72  of a ballast housing  74  formed within one of the support arms  18  so that the ballast  70  is readily exposed on opening of the door  72 . The door  72  is pivotally mounted over housing recess (not shown) formed in the support arm  18  and can be positively latched and unlatched by conventional mechanisms without the use of tools. Electrical connection of conventional nature join the ballast  70  to the luminaire  22  and to a power source (not shown). Remote location of the ballast  70  at a distance from the luminaire  22  allows heat generated by the luminaire  22  to dissipate without affecting operation of the ballast. 
   An indicator (not shown) capable of assuring latching of the support base  12  to the housing support  16  can be employed. Such an indicator can take the form of a “flag” or other device such as is conventional in the art 
   Although the present system  10  has been described relative to particular embodiments thereof, it is to be understood that the invention can be embodied other than is expressly shown and described herein, the scope of the invention being defined by the appended claims.