Airport runway light housing and method of installation

An aircraft guidance light fixture housing for aircraft runways and taxiways includes a generally cylindrical rotationally molded plastic canister or housing member having an intermediate cylindrical wall section which is of an outer diameter slightly less than the inner diameter of the remaining wall sections of said housing member whereby the housing member may be cut in predetermined spaced apart positions to remove a portion of the housing member and permit telescoping one of the remaining sections into the other remaining section. The overall height of the housing member and the rotational position of one housing section relative to the other may be determined by the cutting and reassembly process. A support ring is mounted on the housing member and includes a peripheral flange of a diameter greater than the housing member so that aircraft loads on the light fixture may be transmitted directly to the runway structure and not through the housing. The housing assembly is installed in a runway structure by predetermining the overall height of the housing, cutting the housing member to provide the predetermined height of the housing assembly, installing the housing with one section rotationally positioned relative to the other in a predetermined position and encapsulating the housing and the support ring by adding runway structure material to secure the housing in a predetermined position.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention pertains to a runway or taxiway light fixture 
enclosure or transformer housing of the type which is embedded in the 
runway surface and a method of installing the light housing in accordance 
with various thicknesses of runway structure and clearance requirements 
for the light fixture itself. 
2. Background 
In the art of runway and taxiway aircraft guidance lights of the type which 
are typically mounted at ground level or substantially flush with the 
runway surface, it is often necessary to adjust the enclosure or housing 
for the light fixture in accordance with the overall thickness of the 
runway structure. In the case of directional type aircraft guidance lights 
it is also necessary to be able to adjust the position of the light 
support structure to provide for aiming the light beam along a specified 
azimuth. 
U.S. Pat. No. 3,678,260 to E. W. Beal and assigned to the assignee of the 
present invention describes a typical aircraft guidance light of the type 
wherein the light assembly casing and cover are supported within an outer 
housing embedded in a concrete or asphalt runway. In the light assembly 
illustrated in the Beal patent the light fixture cover, which includes the 
mirror and lens, is arranged to transfer the weight of an aircraft running 
over the light cover to the concrete reinforcement or to the housing 
flange in an indeterminate manner. Moreover, in conventional housings 
heretofore used the flange is not of sufficient diametral extent as to be 
capable of transferring a substantial part of the weight of the aircraft 
to the concrete but instead transmits a substantial amount of the aircraft 
weight to the housing itself which can result in buckling of the housing. 
Prior art flanges are also of a design which is not particularly suited 
for preventing the transfer of rotational loads to the housing if an 
eccentric braking force is exerted by an aircraft tire on the light 
assembly cover during runover thereof. 
Accordingly, there are several features in the provision of an aircraft 
guidance light housing and support flange arrangement which are desirable 
and which have not been provided by prior art housings or methods of 
installation associated therewith. 
SUMMARY OF THE INVENTION 
The present invention provides an improved base or transformer housing and 
support flange for an aircraft guidance light, particularly of the type 
adapted to be disposed at ground level or substantially flush with the 
surface of an aircraft runway or taxiway. The present invention further 
provides an improved method of installing a housing in accordance with the 
invention to provide for the correct height of the light assembly with 
respect to the runway surface and to permit easy adjustment of the light 
beam azimuth or directional characteristics. 
In accordance with one aspect of the present invention there is provided an 
aircraft guidance light housing constructed in such a way that the housing 
may be used for a variety of applications, for enclosing a variety of 
light assemblies and for use in installations where the runway structures 
are of various thicknesses. In particular, the housing is desirably made 
of a molded plastic such as polyethylene or the like and wherein the 
housing may be easily cut in the field and assembled in such a way that 
the overall height of the housing for positioning or locating an aircraft 
guidance light is in accordance with a predetermined dimension, and the 
housing and a supporting ring or flange for the light fixture may be 
rotationally placed in a predetermined orientation of the light fixture. 
In accordance with another aspect of the present invention the aircraft 
guidance light housing is made in such a way that a top section of the 
housing may be slipped in telescoping relationship within a bottom section 
of the housing after the housing has been cut to remove an intermediate 
portion. In this way the overall height of the housing can be adjusted in 
the field without requiring special tools or fabricating equipment. 
Moreover, after field fabrication or adaptation in accordance with the 
aforementioned cutting and section removal procedure the top section of 
the housing can be rotationally adjusted relative to the bottom section so 
that a light fixture support flange mounted on the top section of the 
housing may be oriented to provide a predetermined azimuth or bearing for 
the light beam. 
In accordance with still a further aspect of the present invention an 
aircraft guidance light support structure includes a support ring which 
projects radially beyond the periphery of a molded cylindrical enclosure 
or housing and is connected thereto. The housing is installed in a 
concrete, asphalt, or other runway structure in such a way that aircraft 
or other vehicle loads imposed on the light fixture are transmitted 
through the support ring directly to the runway structure itself and 
aircraft weight or impact loads are not transmitted to the molded housing. 
In accordance with yet further advantageous aspects of the present 
invention the support ring for the light fixture is provided with radially 
relieved surfaces which, when embedded in concrete or other runway 
structure material, reduce the tendency for the support ring and light 
fixture to be rotated due to eccentric rotational forces induced by 
aircraft braking efforts or conventional land vehicle traction efforts 
imposed on the light fixture cover. The support ring may also be provided 
with additional support structure embedded in the runway structure 
including a plurality of elongated bolts to give further strength to the 
housing and support ring to resist tearing the support ring out of the 
runway structure in the event that the light fixture is impacted by a snow 
plow blade or the like. 
The present invention still further provides a method of installing a 
support housing for an aircraft guidance light fixture or the like wherein 
the housing may be adjusted as to its overall height and rotationally 
positioned to provide for orienting the light beam in a predetermined 
direction upon final assembly of the light fixture to the housing itself. 
The method utilizes a novel light fixture enclosure or housing and support 
ring assembly which may be utilized in runways of various thicknesses and 
in applications wherein runway surfaces are overlaid with additional 
layers of concrete or other runway surface material. 
Those skilled in the art will recognize the above described features and 
advantages of the present invention as well as other superior aspects 
thereof upon reading the detailed description which follows in conjunction 
with the drawing.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
In the description which follows like parts are marked thoughout the 
specification and drawing with the same reference numerals, respectively. 
The drawing figures are not necessarily to scale and certain features may 
be shown exaggerated in scale in the interest of clarity. 
Referring to FIG. 1, there is illustrated a vertical central section view 
of an aircraft guidance light of the type which is mounted in a runway or 
taxiway structure along the runway center line, the runway touchdown zone 
or along the edges or threshold of a runway or taxiway, for example. By 
way of example only, a runway structure is illustrated which comprises a 
layer of poured concrete 10 having a generally horizontal aircraft support 
surface 12 formed thereon. Further by way of example, a light fixture or 
assembly 14, comprising a runway centerline guidance light, is shown 
mounted in the runway 10 in such a way that a fixture cover 16 protrudes 
only slightly above the surface 12 sufficiently to project a beam of light 
18 in a predetermined direction along the runway centerline to assist in 
guiding an aircraft during approach, takeoff and traversal along the 
runway itself. 
The light fixture 14 includes a bracket 20 which is disposed within an 
enclosure or housing, generally designated by the numeral 22, which is 
embedded in the runway 10 and provides a clear space 19 for receiving the 
casing of the light fixture. The bracket 20 typically supports a reflector 
23 and other structure associated with generation and projection of the 
light beam 18. The housing 22 comprises a generally cylindrical bottom 
section 26 having a transverse bottom wall 28. The housing 22 includes a 
top section 30 which is also cylindrical and includes a reduced diameter 
wall portion 32, which is of a wall thickness corresponding to an enlarged 
diameter portion 34, although the outer surface 36 of the reduced diameter 
portion 32 is of a diameter slightly less than the diameter of the inner 
surface 38 of the cylindrical side wall 40 of the lower housing section 
26. The wall portions 32 and 34 are joined by a transverse shoulder 37. 
The top section 30 includes an integral reentrant rim 44 in which a series 
of spaced apart bolt clearance holes 46 are formed, see FIG. 2 also, in 
accordance with a predetermined bolt pattern. 
As previously mentioned the housing 22 is preferably suitably molded in one 
piece of a plastic material such as polyethylene or the like and will be 
described in further detail herein in conjunction with FIG. 2 also. As 
illustrated in FIG. 1, the lower housing section 26 has been provided with 
two opposed openings 50 and 52 in which generally annular elastomeric 
grommets 54 have been inserted and for receiving in substantially sealing 
relationship electrical conduit sections 56 and 58 providing a wireway for 
suitable conductor wires leading to and from the light fixture 14. The 
conduits 56 and 58 are slip fitted into the elastomeric grommets 54 
although the openings 50 and 52 may be modified to receive other types of 
fittings for supporting or terminating conduit sections similar to the 
sections 56 and 58. 
The housing 22 is illustrated in its finished assembled condition in FIG. 1 
and is preferably provided as a one piece canister, as illustrated in FIG. 
2, wherein the reduced diameter portion 32 is of a predetermined length, 
is formed integral with the bottom section 26 and is joined thereto 
through a shoulder 55 in the same manner as the portion 32 is joined to 
the top section 30. Accordingly, as initially constructed, the housing 22 
is preferably a one piece structure which is typically shipped to a work 
site for installation without being cut so that the overall height of the 
housing between the bottom wall 28 and the top wall or rim 44 may be 
selectively predetermined at the time of installation. In this regard, as 
illustrated in FIG. 2, and by way of example, once the desired overall 
height of the housing 22 is determined the housing is cut 
circumferentially, if required, along respective cut lines 62 and 64 to 
remove a major part of a reduced diameter transition zone or portion 65. 
The portion 65 initially includes the finally determined reduced diameter 
portion 32 and part of the portion 65, between the wall 40 of the bottom 
section and the reduced diameter portion 32, is removed so that the 
reduced diameter portion 32 may be slipped into the bottom section 26 in 
telescoping relationship as illustrated in FIG. 1. 
When the two sections 26 and 30 of the housing 22 are assembled the annular 
shoulder 37 formed between the wall portion 34 and the reduced diameter 
portion 32 may be brought into registration with a transverse surface 39 
which is formed on the housing section 26 upon cutting the housing 22 
along the cut line 64. However, it is preferred that the shoulder 37 and 
the surface 39 not be brought into force transmitting registration with 
each other if a positional relationship can otherwise be held between the 
rim 44 and the bottom wall 28 during installation of the housing 22 and as 
long as the portion 32 is telescoped at least partially into the lower 
section 26. The distance between the cut lines 62 and 64 may also be 
varied to determine the overall assembled height of the housing as long as 
a section 32 is provided for interfitting the upper and lower housing 
sections. The cut lines 62 and 64 can be moved so that a reduced diameter 
portion using part of the transition section 65 is formed integral with 
the bottom section 26 and is telescoped into the enlarged diameter portion 
34 of the top section 30. 
Referring further to FIGS. 1 and 2, the improved light fixture housing 22 
includes a support ring for the cover 16 and which is generally designated 
by the numeral 70. The support ring 70 includes a generally cylindrical 
opening 72, a transverse top wall 74 and a radially projecting flange 
portion 76 having an outer diameter which is somewhat greater than the 
diameter of the housing sections 26 and 30. The flange 76 is provided with 
circumferentially spaced radially inwardly relieved surfaces 80 forming 
respective recesses. A plurality of threaded holes 84 are interposed in 
the flange 76 between the surface 80 for receiving anchor bolts 86, FIG. 
1, which depend from a downwardly facing surface 87 of the flange 76. 
A second bolt circle defined by a plurality of fastener receiving holes 88 
is also formed in the top wall 74 and a third bolt circle defined by a 
plurality of equally spaced fastener receiving holes 90 is formed in the 
support ring 70 and opening to the surface 87. The pattern of fastener 
holes 88 and 90 may be such that the holes are equally spaced from each 
other and the number of holes may be a total of six holes 88 and a total 
of six holes 90 whereby a rotational spacing interval of at least 
30.degree. may be provided for the light fixture cover 16 with respect to 
the housing 22. The support ring 70 is secured to the rim 44 by fasteners 
91 which project through the holes 46 into the tapped or threaded holes 
90. 
As illustrated in FIG. 1, the light fixture cover 16 is secured to the 
support ring 70 by fasteners 94 which are threaded into the holes 88. 
Typically, the flange 76 is entirely encapsulated by the concrete runway 
structure and, thanks to the radially projecting flange, vertically 
downward directed forces, viewing FIG. 1, imposed on the light fixture 14 
by the weight of an aircraft wheel passing thereover are transmitted from 
the cover 16 to the support ring 70 and to the runway structure through 
the flange 76. Moreover, any tendency to lift the support ring 70 
vertically upward due to impacting the light fixture cover 16 by a snow 
plow blade or the like will be resisted by the flange 76 since it is 
totally embedded in the concrete runway structure. The anchor rods or 
bolts 86 also assist in resisting a vertically upward lifting force or 
tipping force exerted on the fixture 14 and the support ring 70. 
Accordingly, substantially all forces imposed on the fixture 14 are 
transmitted through the support ring 70 to the runway 10 and are not 
imposed on the housing sections 26 or 30. In this regard also, any 
tendency to rotate the support ring 70 about a vertical central axis 99, 
FIG. 1, is resisted by the flange 76 due to the recesses which are formed 
by the surfaces 80 and filled with the runway structure material. 
Therefore, any rotational loads imposed on the light fixture 14 such as 
due to braking action of an aircraft tire passing over the light fixture 
are transmitted through the support ring 70 directly to the runway 
structure and substantial loading of the housing section 30 is avoided. 
The improved aircraft guidance light housing and support ring assembly of 
the present invention is also adapted to be used in installations wherein 
the required overall height of the housing is greater than the length of 
an uncut housing member 22 or in installations where a runway or taxiway 
has been resurfaced by applying an additional layer or layers of concrete 
or other runway structure material over an existing runway. Referring to 
FIGS. 3 and 4 by way of example, in FIG. 3 there is illustrated an 
installation of a cut and reassembled housing 22 which has been embedded 
in a runway structure 100. The housing 22 could also be an uncut version 
having the full transition section or portion 65 intact assuming, of 
course that the thickness of runway 100 required such. The runway 100 may 
also be the first layer of a multi-layer runway structure. In FIG. 3, in 
particular, there is illustrated a partially finished runway structure 
wherein a first layer 101 has been poured around a housing 22 which may 
have been cut to determine its overall height or left uncut as required by 
the overall thickness of the runway structure. 
The top surface 102 of the runway 100 is prepared for the installation of a 
second housing, similar to the housing 22, but designated by the numeral 
104 in FIG. 4. In preparing a multi-layer runway for the receipt of a 
second layer of concrete and the receipt of a housing 104, during the 
preparation of the first layer 101 of runway 100 a removable cover plate 
108, FIG. 3 is installed over the top rim 44 of the housing 22 to prevent 
debris from falling into the space 19. Upon completion of construction of 
the runway layer 101 the plate 108 is removed and a second housing 104 can 
be prepared for installation. 
The housing 104 may be formed in a selected one of at least two ways by 
cutting two housings 22 to form respective housing sections 106 and 108. 
The housing section 106 may be formed, for example, by cutting a housing 
section similar to the housing section 30 in FIG. 1 above the transition 
to the reduced diameter portion 32 or, in other words, between the rim 44 
and the shoulder 37 so that the housing section 106 has a cylindrical side 
wall 107 of the same diameter as the enlarged diameter wall 34 of the 
housing section 30. The housing section 108 is prepared by cutting another 
housing 22 to form a housing section virtually identical to the housing 
section 30 but of the requisite length to place a support ring 70 in 
proximity to the finished runway surface 110 which is finished formed by 
applying a second layer of concrete, for example, to form a runway section 
112. The housings 22 and 104 are, as illustrated in FIG. 4, secured 
together by fasteners 114 by placing the rim 44 of the housing section 106 
adjacent to the rim 44 of the housing 22. Alternatively, the housing 104 
may be formed in the same manner as the formation of a housing as 
illustrated in the FIG. 1 embodiment but modifying the bottom wall 28 to 
have an opening of the same diameter as athe opening 72 and also providing 
bolt clearance holes similar to the clearance holes 46 formed in the rim 
44. In the installation of the housing illustrated in FIG. 4, a second 
removable cover plate 122 is preferably installed with removable fasteners 
94 to prevent debris from falling into the housing space 119 during 
construction of the runway layer or section 112. 
Accordingly, the housing 22 may be used in several ways alone or in 
combination with additional housings 22 to construct a light fixture 
housing having a sufficient depth to accommodate various types of light 
fixtures and to position the fixture support ring 70 in the desired 
elevation position with respect to the runway surface as well as in the 
desired rotational position of the light fixture for orienting or aiming 
its light beam in a desired azimuth. 
Thanks to the provision of the housing 22 as a relatively lightweight 
plastic structure it may be easily cut in the field at the installation 
site by conventional hand or power tools without requiring special 
fabrication techniques after the initial fabrication or molding operation. 
Those skilled in the art will further appreciate that the use of one or 
more of the housings 22 in a cut or uncut configuration may be used in 
conjunction with the construction of runways having one or more layers of 
runway material. Materials may be used other than concrete such as 
asphalt, and an asphalt layer may be provided over a concrete layer in 
either new construction or wherein a concrete layer is provided as an 
existing base structure. Moreover, the housing and method of the present 
invention may be used in some instances wherein an asphalt or concrete 
layer is constructed over an existing relatively shallow base structure 
having a prexisting recess or no recess for receiving a portion of a light 
fixture 14 or a portion of a previous light fixture installation. 
The overall height of a housing 22 may be varied selectively in accordance 
with the foregoing description for cutting the housing and installing it 
in applications where the overall height of the finished installation is 
less than the height of one uncut housing 22. Moreover, the housing 22 may 
be provided in selected different overall heights as initially constructed 
and, of course, in different diameters as required by the various types of 
light fixtures to be housed thereby. The housing 22 may also be used in 
non-loadbearing applications without the support ring 70, that is in 
guidance light installation which would not be subject to runover by an 
aircraft or other vehicle. In all embodiments illustrated the upper 
separate section of the housing such as the sections 30 and 108 may be 
rotationally positioned relative to the respective lower sections in a 
selected position before encapsulation of the housing by the runway 
material. Conventional alignment fixtures may be used to position the 
upper housing sections 30 and 108, for example, before encapsulation. 
The preferred methods of installing the housing 22 and 104 are believed to 
be inherently described above in conjunction with the description of the 
installations illustrated in FIGS. 1, 3 and 4. However, referring to FIG. 
1, for example, in a typical installation of a housing 22 the overall 
height of the runway 10 is determined and compared with the overall height 
of an uncut housing 22. If the overall height of the uncut housing plus 
the height or axial extent of the support ring 70 and the cover 16 require 
cutting of the housing 22 a cut is made along the cut lines 62 and 64 to 
provide the requisite height of the housing 22 in its cut form to 
accommodate the overall height requirements of the installed light fixture 
assembly as illustrated in FIG. 1. The support ring 70 is then assembled 
to the housing section 30 and the housing section 30 assembled in 
telescoping relationship into the housing section 26. The housing section 
26 may be previously placed in its predetermined position and connected to 
the conduit sections 56 and 58. The overall height of the housing 22 
including the support ring 70 may then be determined by adjusting the 
position of the housing section 30 relative to the housing section 26. As 
mentioned previously, at least a slight clearance should be provided 
between the shoulder 37 and the surface 39. The exact axial position and 
rotational position of the support ring 70 and housing section 30 may be 
provided by a suitable locating jig or fixture. Once the position of the 
housing section 26 and the housing section 30 are determined the runway 
material is poured or otherwise applied to encapsulate the housing and 
support ring assembly. The application of runway material may be 
accomplished in stages such as, if pouring concrete, pouring enough 
concrete to anchor the housing section 26 and then making any final 
adjustments in the exact position of the support ring 70 and housing 
section 30 by axially moving this assembly relative to the housing section 
26 and also rotationally positioning the assembly of the housing section 
30 and the support ring 70 relative to the housing section 26. The 
remaining concrete may then be poured to completely encapsulate the 
housing and support ring assembly. 
The installation of the housing assembly illustrated in FIGS. 3 and 4 may 
be carried out in substantially the same manner as described above for the 
housing installation illustrated in conjunction with FIG. 1 with the 
exception that two positional measurements are taken, one each for the 
housing 22 and the housing 104 so that a final position of the support 
ring relative to the runway surface 110 may be provided. Those skilled in 
the art will recognize that the basic method of installing the housings 22 
and 104 may be carried out in existing runway structures by drilling or 
excavating a hole in an existing runway of sufficient diameter to receive 
a housing 22 and/or a housing 104 and also providing sufficient space 
around the housing to apply filler or encapsulating material between the 
existing runway structure and the abovementioned clearance hole. After the 
housing is fabricated in accordance with the method of the present 
invention and installed with a suitable jig or fixture to position it 
relative to the finished working surface of the runway, the abovementioned 
material is added into the clearance hole or excavation to encapsulate the 
housing as with new runway construction. 
Although preferred embodiments of the present invention have been described 
herein in detail those skilled in the art will recognize that various 
substitutions and modifications may be made to the specific embodiments 
described without departing from the scope and spirit of the invention as 
recited in the appended claims.