Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
Case 2444
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m is invention concerns luminaires and illuminated
signs. It is particularly directed to a pedestrian cross-walk
sign and luminaire combination, although not restricted thereto.
In an outdoor luminaire which is required to be
rigidly interconnected to a boom the resultant structure is
usually a compromise between cost, weight and rigidity. Many
such luminaires employ cast housings in order to withstand the
strong localized forces which may be imposed upon the housing
especially in the region of the slip fitter joint. Even where
the cagtings are made from aluminum or magnesium, the weight
of a cross-walk luminaire is substantial.
Considerable weight and cost economy is effected
where the luminaire is constructed from sheet metal,
especially sheet aluminum, but several difficulties arise.
Thus th~ localized stress in the area of the 51ip fitter joint
may eventually induce stress cracking of the metal. In the
cross-walk sign and luminaire combination under consideration
it was additionally found that only slight flexing of the casing
permitted the escape of light from the luminaire to dazzle
oncoming traffic. A further, related problem in such
combination concerns the torsional rigidity of the structure.
The housing is generally of s~uare prismatic shape with
window openings being provided in three adjacent surfaces
1 thereof to accommodate transparent or translucent window
i or lens material. Since the window openings occupy a major
proportion of the surfaces in which they are located the
inherent rigidity o the integral structure is largely destroyed.
, Under wind generated loading the lateral twisting of the housing
may be sufficient to dectroy the sealing between the window~
or lens and their surrounding openings. - ~
It is an object of my invention to provide an -I
aforesaid type of luminaire wherein the variou~ forces to which
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the erected construction is exposed may be more readily
withstood.
In a luminaire having a housing which comprises a
pair of generally opposed end walls, a pair of generally
opposed side faces interconnecting the end walls and optionally
one or more additional faces having perimetric portions in
common with each said end wall and said side face, at least
one of the faces having a substantial window opening therein,
I provide a torsion tube or beam or other tor3ion resisting
means which rigidly interconnects between the end walls of the
housing internally thereof. A rigid connection to a suspending
mast, boom or bracket may be made directly to the torsion tube
or to a slip fitter connected thereto. Where the slip fitter
locates on one of the faces of the housing, a rigid bracket is
provided internally of the housing to interconnect between the
torsion tube and the slip fitter. As an alternative the
! torsion tube itself may be deformed so as to interconnect to
the slip fitter without necessitating any intermediate bracket.
I The luminaire will generally be a 5 or 6 sided polyhedron such
; 20 as a triangular prism, a truncated triangular pricm and a
~- rectangular prism, for example: other shapes are not excluded,
! the above examples nt being exhaustive.
In the accompanying drawings which illustrate a
preferred constructive embodiment of the invention,
Figure 1 is a sketch ghowing a pair of luminaires
installed above a pedestrian cross-walk;
Figure 2 shows a luminaire of Figure 1 in a
perspective, partially broken away view to reveal constructi~nal
detail of the interior;
Figure 3 is a view taken along 3-3 of Figure 2.
Referring to Figures 2 and 3 wherein the luminaire
of my invention is indicated generally by the numeral 10, this
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Case 2444
may be seen to comprise a housing including a pair of opposed
end walls 12, 14 interconnected by a pair of side faces 16, 18.
The housing further comprises a top face 20 and a bottom face
22 each of which has perimetric portions in common with end
walls 12, 14 and side faces 16, 18. End walls 12, 14 and top
face 20 are folded from a unitary sheet of aluminum. Side
faces 16, 18 and bottom ~ace 22 are sub~tantially comprised
respectively by windows including frames 24, 26, 28 formed
from extruded aluminum section. In each frame is respectively
sealed a light transmitting window material 17, 19, 23 which
may be a plastic composition or glass. Side faces 16, 18 are
unified with end walls 12, 14 and top wall 20 by any suitable
means such as rivetting, bolting or brazing, for example.
Bottom face 22 is hinged along one side thereof at 29 to the
lower edge of face 16; the opposed side of face 22 is supported
from the lower edge of face 18 by slips 30. ~ottom face 22
may thus be released from its normal position to permit it
to swing downwardly, thereby providing access to the interior
of luminaire 10 for maintenance purposes.
Luminaire 10 i~ provided with a downwardly directed
source of illumination comprising a pair of (250) watt high
+rof~
A intensity discharge lamps 70 and concaveAreflector 72. With
particular reference to Figure 1, luminaire 10 is normally
suspended from a boom 60 adjacent the vehicular approach side
of a pedestrian cross-walk, and downwardly dire~ted light i~
focussed rearwardly by angled reflector 72 to illuminate the
cros~-walk. Cut off screen~ 32, 34, which form the lower
portions of side faces 16, 18 respectively, reduce the angle
of divergence of downwardly directed light, screen 34 particularly
r~stricting the escape of light towards oncoming traffic. The
general method of rigidly suspending traffic signs and
luminaires rigidly from a boom 60 is by the use of a spring
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loaded coupling interposed between the end of the boom and a
slip fitter or other means located externally or intexnally of
the housing of the luminaire. This coupling reduces vibrational
shock transfer between the boom and the luminaire by permitting
slight relative movement corresponding to an angular deflection
in a major surface of the luminaire of about 7. m e optical
geometry of the luminaire lO can be designed to accommodate
this permitted movement whilst restricting the escape of
illumination that would dazzle oncoming traffic. However
further relative movement such as may occur by localized
flexing of the housing in ~he region of the slip fitter, or
by torsional distortion of the housing, may permit the e~cape
of dazzling illumination. Such further relative movement
is undesirable for other reasons as previously explained.
~he light weight, highly windowed structure so far
described i8 insufficiently rigid to withstand the dynamic
loading forces to which it is normally exposed when erected.
me stiffening and mounting means which I employ so as to
` overcome the problems spoken of comprise a torsion tube 40
which rigidly interconnects end walls 12, 14 internally of the
luminaire 10. Such interconnection with the end walls is
made through flanges 42, 44, which secure to the end walls
with bolts 46. Flanges 42, 44 are each provided with a collar
portion 43, 45 and are slidable along tube 40. Each collar
portion has at least one radial locking screw 47, 49. In
assembling torsion tube 40 within the housing of luminaire to
flanges 42, 44 are introduced onto tube 40 without being locked
in position. End walls 12, 14 are maintained with a predetermined
spacing and tube 40 is offered into place within the housing.
The flanges 42, 44 are then secured to respective end walls 12,
14 with bolts 46 or other mean~, following which locking screws
47, 49 are tightened to unify the torsion resisting assembly.
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The luminaire 10 rigidified in the above described
manner may be attached to a boom by a slip fitter means
provided on either of the end walls 12 or 14 and which secures
directly to a flange 42 or 43. As an alternative torsion tube
40 may project externally of the housing of luminaire lO to
provide a direct coupling means to suspension boom. In the
presently described embodiment it is preferred to suspend
luminaire lO ~rom a boom 60 which interconnects to the top
face 20 of the luminaire. A slip fitter 50 is secured to
face 20. Slip fitter 50 is integrally connected to the torsion
resisting means by a U shaped bracket 52 the legs of which are
welded to tube 40 at 54. The distal ends o bracket 52 are
overturned to form flanges 58 which underlay top face 20 and
which bolt dixectly to slip fitter 50.
The bight portion 56 of bracket 52 forms a convenient
means from which a high intensity discharge lamp 64 i9 mounted
for the purpose of illuminating the window~ 17 and 19 which
comprise the sign portion of luminaire lO. Current control
ballasts 66 for lamps 64 and 70 are ~upported from tube 40 ~ ~ -
either by being attached directly thereto, or indirectly sup-
ported on trays 68 which couple to tube 40 which U bolts 69.
Such ballasts may be positioned externally of luminaire lO i
desired.
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