Aircraft reading light

A lighting apparatus includes a housing and a lamp support assembly that is normally retained in but removable from the housing. The lamp support assembly includes coaxial inner and outer sleeves, and a lamp socket mounted on one of the sleeves. The inner sleeve is movable relative to the outer sleeve between a braced position in which the lamp support assembly is retained in the housing, and a released position in which the lamp support assembly is released for removal from the housing. A lamp is received in the socket, and the inner sleeve is biased toward the braced position when the lamp support assembly is positioned in the housing so that the lamp support assembly is retained in the housing.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates generally to lighting devices and, more 
particularly, to a reading light constructed in a manner to permit easy 
manual replacement of burnt-out lamps while at the same time being tamper 
resistant. 
2. Discussion of the Prior Art 
It is known to provide passenger reading lights in aircraft, buses, trains 
and the like, which permit individual passengers to direct a reading light 
onto a book or other subject to be illuminated. 
In conventional lighting devices of this type, it is common to permit the 
replacement of a burnt-out bulb by providing structure that may be 
withdrawn from the lamp housing, exposing the bulb for manual removal from 
the device. Typically, a tool is required to unfasten the removable 
structure from the lamp housing so that passengers will not tamper with 
the device. However, such constructions are also difficult for trained 
maintenance personnel to manipulate, and known constructions commonly 
require direct or close manual contact with the lamp during a replacement 
operation, resulting in a high risk of burns to the person carrying out 
replacement of a lamp. 
It is also known to provide a construction including a lamp support 
assembly that is retained in a ball-shaped housing through the cooperation 
of detents on the support assembly which engage a stepped region of the 
housing. In this device, removal of the support assembly is carried out by 
manually pulling on the assembly until the force of the detents is 
overcome and the assembly pulls free of the housing. One problem 
encountered with this type of construction resides in the difficulty with 
which the assembly is pulled from the housing. Typically, in order to 
reduce tampering with the device, the detents are formed with very little 
flexibility so that a relatively strong force must be exerted on the 
assembly to pull it free from the housing, thus complicating in-travel 
replacement of a lamp. 
OBJECTS AND SUMMARY OF THE INVENTION 
It is an object of the present invention to provide a lighting apparatus 
which permits quick, easy replacement of a burnt-out lamp, while being 
resistant to tampering by passengers and others who are unaware of the 
method used in carrying out a replacement operation. 
Another object of the invention is to provide a lighting apparatus in which 
a lens is recessed within the lamp housing to reduce the temperature of 
surfaces contacted by passengers during adjustment of the position of the 
lamp housing during use. In addition, the lens and lamp are both mounted 
on a removable lamp support assembly in such a way as to permit simplified 
removal of the lamp from a socket on the assembly, and protect maintenance 
personnel against accidental electrical shocks or burns during replacement 
operations. 
Yet another object of the present invention is to provide a lighting 
apparatus that includes structure for permitting ease of assembly within 
an aircraft, bus, train or the like, and which permits the lamp housing to 
be secured in any desired use position. 
In accordance with these and other objects of the invention evident from 
the following detailed description, a lighting apparatus constructed in 
accordance with the present invention includes a housing and a lamp 
support assembly normally retained in but removable from the housing. 
The lamp support assembly includes coaxial inner and outer sleeves, and a 
lamp socket mounted on one of the sleeves. The inner sleeve is movable 
relative to the outer sleeve between a braced position in which the lamp 
support assembly is retained in the housing, and a released position in 
which the lamp support assembly is released for removal from the housing. 
A lamp is received in the socket. 
A biasing means is provided for normally biasing the inner sleeve toward 
the braced position when the lamp support assembly is positioned in the 
housing so that the lamp support assembly is retained in the housing. The 
biasing means permits removal of the lamp support assembly by allowing 
manual movement of the inner sleeve against the biasing force to the 
released position. 
Preferably, the outer sleeve includes a number of longitudinally extending 
fingers each provided with an outwardly directed detent, and the fingers 
are deflectable radially to permit passage of the outer sleeve through the 
opening when the inner sleeve is in the released position. The inner 
sleeve includes an outer circumferential bracing surface which abuts 
against the fingers of the outer sleeve when the inner sleeve is oriented 
in the braced position so that the fingers are prevented from deflecting 
radially inward and the lamp support assembly is retained in the housing. 
The bracing surface is movable away from the fingers when the inner sleeve 
is in the released position to allow deflection of the fingers so that the 
lamp support assembly may be moved through the opening. 
By constructing a lighting apparatus in accordance with the present 
invention, numerous advantages are realized. For example, by providing a 
lamp support assembly as described, it is possible for maintenance 
personnel to remove the support assembly manually from the housing and 
replace the lamp without the need for a tool. Also, because of the method 
used to release the support assembly for removal from the housing, it is 
difficult for a person without knowledge of the method to perform the 
operation. Thus, the construction is tamper resistant. 
Another advantage achieved through the use of the present invention resides 
in supporting the lamp within a socket provided on the lamp support 
assembly so that when the assembly is removed from the housing the lamp 
may be removed by simply turning the assembly upside down allowing the 
lamp to fall from the socket. This construction also prevents the person 
performing the replacement from being burned by the lamp. 
Also, because the lamp is removed from the housing with the support 
assembly, the lamp is removed from contact with the electrical terminals 
within the housing, and accidental shocking of the maintenance personnel 
is prevented.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
A lighting apparatus constructed in accordance with the preferred 
embodiment of the present invention is illustrated in FIG. 1, and includes 
a housing assembly 10 that is supported for universal movement within a 
mounting assembly 12. 
As shown in FIG. 5, the housing assembly includes a ball-shaped housing 14 
formed of a thermoplastic material and having an interior space 16, a 
first opening 18 connecting the interior space to a region above the 
housing, a second opening 20 extending downward from the interior space, 
and a plurality of vent openings 22 connecting the interior space with the 
region exterior of the housing for ventilating the space. The interior 
circumferential surface of the housing is cylindrical and is defined by a 
diameter that is slightly larger than the diameter of the second opening 
20. This difference between the two diameters creates a step or ramp 24 
between the interior space 16 and the opening 20. 
The exterior surface of the housing 14 is provided with a recessed region 
30, and a radial through-hole 32 is provided in communication with the 
first opening 18. A first electrical terminal 34 is received within the 
through-hole, and a second electrical terminal 36 is secured to the edge 
of the first opening 18 and extends into the opening a predetermined 
distance beyond the first terminal 34. The terminals 34, 36 are formed of 
beryllium copper and snap onto the housing 14. The electrical circuit 
including the apparatus is illustrated in FIG. 10, and simply includes a 
first conductor connected between the terminal 36 and a power source, and 
a second conductor connected between the terminal 34 and ground. 
Returning to FIG. 5, a neoprene rubber terminal guard 38 is sized for 
receipt over the upper end of the housing and protects the terminals 
against physical contact with objects outside the apparatus. 
The mounting assembly includes an annular flange 40 formed of thermoplastic 
material and having an inner circumferential surface shaped to receive the 
outer circumferential surface of the housing 14. The flange 40 is formed 
of a plurality of connected, longitudinally extending fingers, and a 
locking ring assembly 42 is provided which encircles the flange across the 
tips of the fingers, and holds the fingers against the outer 
circumferential surface of the housing. 
As shown in FIG. 2, the locking ring assembly 42 includes a stainless steel 
split ring 44 having two slots 46 provided on one end thereof and a clasp 
48 on the other end. The clasp 48 may be fastened in one of the slots 46 
to secure the housing within the flange. When the clasp is connected to 
the nearest slot a minimal amount of compression force is asserted on the 
housing so that the housing is universally movable within the flange. 
Thus, the position of the apparatus may be adjusted by a passenger, but 
enough force is exerted on the housing to prevent the housing from 
vibrating out of position. When the clasp is connected to the farthest 
slot the compression force exerted on the housing is sufficient to lock 
the apparatus at a specific position. 
The flange 40 includes a number of flexible feet 50 extending radially 
outward from the bases of some of the fingers. These flexible feet hold 
the flange on a support panel 52, as shown in FIG. 6, and may be deflected 
in a radial direction during assembly on the panel to lock the flange in 
position. A pin 54 extends into the flange and is received within the 
recessed region 30 on the outer surface of the housing 14. The pin 54 
prevents the housing from being moved beyond predetermined limits in order 
to protect against the possibility that the electrical wires to the 
apparatus will become tangled during movement of the housing. 
A lamp support assembly 56 is normally received within the housing. As 
shown in FIG. 3, the assembly 56 includes an outer sleeve 58, an inner 
sleeve 60, a lens 62, a reflector 64, and a socket 66. The outer sleeve 58 
is formed of thermoplastic material and is annular in shape. The outer 
sleeve includes a radially inwardly directed flange 68 at the lower end 
thereof against which the inner sleeve 60 abuts during normal use. A 
number of longitudinally extending fingers 70 are provided on the outer 
sleeve. The inner diameter of the outer sleeve is slightly greater at the 
free end of the fingers than it is along the remainder of the sleeve, and 
each finger includes an outwardly directed detent 72 at the free end 
thereof as well as an inwardly directed barb 74. The barb separates the 
remainder of the sleeve from the region of increased diameter. 
The inner sleeve 60 is also formed of thermoplastic material and is of 
annular shape, being of a size adapted to fit within and be coaxial with 
the outer sleeve. The inner sleeve 60 includes an outer circumferential 
surface provided with a small diameter region 76 and a large diameter 
region 78. An annular groove 79 is formed in the outer circumferential 
surface between the small diameter and large diameter regions, and a 
small, stepped sloping region 80 extends between the annular groove and 
the large diameter region. This stepped region defines a bracing surface 
which abuts the inner circumferential surface of the free ends of the 
fingers 70 of the outer sleeve 58 when the inner sleeve 60 is received in 
the outer sleeve and moved against the flange 68, as shown in FIG. 6. 
Turning to FIG. 5, the inner sleeve 60 includes an inner circumferential 
surface provided with two longitudinally spaced rows of inwardly directed 
projections 82 adapted to receive and hold the lens within the inner 
sleeve. The rows of projections 82 are positioned well within the inner 
sleeve in order to protect the passenger from inadvertently contacting the 
lens. Preferably, the projections are located closer to the upper end of 
the inner sleeve than to the lower end to protect the lens from contact 
during adjustment of the position of the housing. 
The upper end of the inner sleeve defining the large diameter region 78 
includes four longitudinally extending arms 86 which permit some 
flexibility of the bracing surfaces. However, as shown in FIG. 4, each arm 
radially supports two of the fingers 70 of the outer sleeve 58 and 
prevents the fingers from being deflected radially inward when the inner 
sleeve is positioned against the flange 68, as shown in FIG. 6. The inner 
circumferential surface of the inner sleeve includes an annular groove 84 
within which the reflector 64 is received and held. This groove 84 is 
formed at the free ends of the arms 86. 
Returning to FIG. 3, the lens 62 is formed of any conventional transparent 
or semi-transparent material and may be of any desired shape in order to 
form and direct light from the lamp in a predetermined manner. The lens 62 
includes an outer circumferential edge sized for receipt between the 
longitudinally spaced rows of projections so that the lens may be snap-fit 
between the projections and retained on the inner sleeve. Because the lens 
is recessed within the assembly, it is rendered less accessible to 
passengers, thus reducing the amount of cleaning that is necessary and 
protecting against lens scratching or breakage. 
The reflector 64 is formed of thermoplastic material and is sized for 
snap-fit receipt within the annular groove 84. The socket 66 is formed of 
cadmium plated brass and is received in the distal end of the reflector. 
As shown in FIG. 5, the socket includes a pair of slots 88 adapted to 
receive two pins 90 provided on the lamp 92. The lamp is preferably a 
halogen lamp, and is supported in the socket 66 with one contact extending 
beyond the distal end of the socket and the pins 90 extending through the 
slots 88. The lighting element of the lamp 92 is disposed within the inner 
sleeve between the reflector 64 and the lens 62. 
By providing a snap-fit connection between the various components of the 
apparatus, secondary attachment operations such as bonding, riveting, or 
ultrasonic welding are obviated. 
During normal use of the lighting apparatus, as shown in FIG. 6, the lamp 
support assembly 56 is positioned within the housing, and is retained in 
position by the detents 72 on the fingers 70 of the outer sleeve, which 
engage the step or ramp 24 defined within the housing. The terminal 34 
biases the inner sleeve 60 against the flange 68 of the outer sleeve 58, 
and the stepped and large diameter regions 78, 80 of the inner sleeve abut 
against and brace the fingers against inward radial movement. 
In order to replace the lamp 92, as shown in FIG. 7, the inner sleeve 60 is 
manually forced longitudinally into the housing 14 against the biasing 
force exerted by the terminal 34 which is deflected away from the lamp 
during this upward movement of the inner sleeve, and the terminal 36 
slides along the outer surface of the socket. This upward movement of the 
inner sleeve 60 removes the bracing surface of the stepped sloping region 
80 from contact with the fingers 70 of the outer sleeve, and provides 
enough clearance between the fingers and the inner sleeve to permit 
radially inward deflection of the fingers sufficient to enable the detents 
72 to ride over the step or ramp 24 and out of the opening 20 of the 
housing 14. 
Preferably, the outer sleeve 58 is constructed to permit deflection of the 
detents 72 upon the exertion of a force of two pounds or less so that once 
the inner sleeve is moved from the braced position, shown in FIG. 6, to 
the released position, shown in FIG. 7, removal of the assembly 56 
requires very little force. As the outer sleeve 58 is pulled from the 
housing, the barbs 74 engage a side of the annular groove 79 in the inner 
sleeve so that the inner sleeve is pulled from the housing with the outer 
sleeve, as shown in FIG. 8. 
Thereafter, as shown in FIG. 9, the lamp 92 is removed from the socket 
simply by turning the lamp support assembly 56 upside down and allowing 
the lamp to fall from the socket 66. 
Although the invention has been described with reference to the preferred 
embodiment illustrated in the attached drawing figures, it is understood 
that substitutions may be made and equivalents employed herein without 
departing from the scope of the invention as set forth in the claims.