Not Applicable
Not Applicable
1. Field of the Invention
The present invention relates to light emitting diode assemblies that are useful to illuminate the interior of a vehicle, such as an aircraft, and more particularly to tubular assemblies having a housing that contains a plurality of light emitting diodes.
2. Description of the Related Art
Aircraft cabins have been illuminated by fluorescent lighting systems. The disadvantages of that type of lighting include the relatively short life of the fluorescent lamp, significant weight of the ballast, heat production, generation of radio frequency interference (RFI), and fragility.
One solution to counter the problems identified above has been to use an assembly of light emitting diodes (LED). U.S. Pat. No. 6,158,882 describes an aircraft lighting system which employs a plurality of LED's mounted in a linear array to form a lighting strip. Such a strip can be used to wash a wall or ceiling of the aircraft cabin with light. The electrical power to illuminate the LED's is furnished from a DC power supply that includes a mechanism for adjusting the voltage to control the level of illumination provided by the lighting strip. This enables the light intensity, or brightness to be varied depending upon the outside light level and activity of the passengers. When the aircraft is flying in daylight, the LED lighting strip usually is driven at a voltage level which provides maximum illumination. At nighttime, that maximum illumination level may interfere with the ability of occupants to sleep or see through the plane's windows, especially upon landing. Therefore, a lower interior illumination level is preferred at night.
In addition to incorporating LED strips into new aircraft, it is desirable to retrofit older aircraft with this type of lighting. Many older planes have conventional fluorescent lighting system that uses lamp tubes with a pair of electrical connector pins at each end. Each pair of pins fits into a socket of the light fixture which mechanically holds the fluorescent tube in place, as well as electrically connects the tube to the power source. A fluorescent light fixture can be readily modified to accept an LED lighting strip by removing the ballast and connecting the 110 VAC power from the aircraft directly to the sockets. The LED lighting strip for this application has a full wave rectifier to convert the alternating current into direct current. A sufficient number of light emitting diodes are connected in series so that voltage across each one conforms to the diode's rating.
A standard fluorescent lamp tube is mounted in the light fixture by sliding the connector pins into end sockets and then turning the tube 90° so that the pins engage electrical contacts in the sockets. The fluorescent lamp tube emits light omnidirectionally and its orientation in the sockets is of no consequence. Specifically, it does not matter which pin is inserted first into the socket or the direction that the tube is rotated to make electrical contact. Thus even though the position of the sockets with respect to the cabin walls may vary a fluorescent lamp tube can be used with a different aircraft makes and models.
However, that is not the case for LED lighting strips in which each LED emits light at a narrowly angled conical path. Therefore, a LED lighting tube retrofitted into the existing fluorescent light fixture may not be oriented to emit light in the desired direction within the aircraft. Thus a need exists to be able to adjust the orientation of the LED lighting tube in the sockets of a modified fluorescent lighting system.
A lighting assembly comprises a housing to which a light source is mounted. In a preferred embodiment, a plurality of light emitting diodes is within the housing and directs light at a relatively narrow angle through a transparent portion of the housing.
A swivel connector is provided to mechanically and electrically connect the lighting assembly to a light fixture. The swivel connector has a rotary fitting attached to the housing, a contact cap adjacent and rotatable with respect to the rotary fitting, and a coupling for engaging a light fixture. A locking member releasably engages at least one of the contact cap and the rotary fitting and a release sleeve operates the locking member to selectively enable and restrict rotation motion between the contact cap and the rotary fitting.
In one embodiment of the present invention, the locking member comprises one or more fingers that project from the contact cap and selectively engage the rotary fitting. The release sleeve has a first position in which it forces each finger against the rotary fitting to create friction that impedes movement between the rotary fitting and the contact cap, thereby maintaining the orientation of the plurality of light emitting diodes with respect to the light fixture. In a second position of the release sleeve, each locking member finger is released from the rotary fitting so that movement may occur between the rotary fitting and the contact cap. This latter position allows the orientation of the LED's to be adjusted.
In another embodiment, the swivel connector has a first torsion spring that winds in one direction around and releasably engages the rotary fitting. The contact cap engages one portion of the first torsion spring and the release sleeve engages another portion of the first torsion spring. The engagement of the first torsion spring with the rotary fitting resists rotation of the housing with respect to the contact cap, thereby holding the orientation of the housing fixed. The release sleeve can be moved with respect to the contact cap to release the holding effect and allow the position of the housing to be changed so that the direction of the emitted light is altered. Specifically, that relative motion loosens the engagement of the first torsion spring with the cylindrical section of the rotary fitting, thereby enabling the housing to rotate with respect to the contact cap.
With initial reference to
With reference to
A separate torsion spring 42 and 44 is located in each of the cylindrical section grooves 34 and 35, respectively. In the normal relaxed state, each torsion spring 42 and 44 firmly engages the outer surface of the cylindrical section 32 of the rotary fitting 28. One end of the first torsion spring 42 has a relatively long tab 46 projecting radially outward while the other end of that spring has an outwardly projecting shorter tab 50. Similarly, the second torsion spring 44 has a relatively long tab 48 projecting radially outward at one end and an outwardly projecting shorter tab 52 at the other end. The two torsion springs 42 and 44 have identical construction, however, they are oriented in reversed directions in the grooves 34 and 35 of the rotary fitting 28. That is, the longer tab 46 of the first torsion spring 42 is located closer to the base 30 of the rotary fitting 28 than the shorter tab 50 of that spring. The shorter tab 52 of the second torsion spring 44 is located closer to the base 30 than its longer tab 48. Thus the first and second torsion springs 42 and 44 are wound in opposite directions around the cylindrical section 32.
A contact cap 54 extends over the cylindrical section 32 of the rotary fitting 28 and has a circular base plate 56 across the remote end of the cylindrical section. The circular base plate 56 has a perimeter from which a plurality of fingers 58 project toward the housing 12. The contact cap 54 is able to rotate about the cylindrical section 32 and one of the fingers 58 has an internal ridge 64 that strikes the stops 40 on the outer annular flange 36 of the rotary fitting 28 to limit that rotation to approximately 180 degrees. The widths of the fingers and spacing there between vary as seen the cross sectional view of
Two electrical terminals 22 project outwardly from the circular base plate 56 of the rotary fitting 28. The electrical terminals 22 are adapted to mate with a standard socket 21, 23 of a fluorescent light fixture. Wires (not shown) connect the electrical terminals 22 to the circuit board 24 within housing 12 thereby enabling electrical power to be applied to the LED's 26.
With additional reference to
A release sleeve 68 extends around the contact cap 54 and the cylindrical section 32 of the rotary fitting 28, as shown in
The release sleeve 68 has a pair of L-shaped grooves 78 and 80 which respectively receive the longer tabs 46 and 48 of the two torsion springs 42 and 44, as seen in
With reference to
To change the direction of the light after the first lighting assembly 10 has been inserted in the light fixture sockets 21 and 23, the installer grasps the light assembly housing 12 with one hand and the release sleeve 68 with fingers of the other hand. The release sleeve is then rotated in the opposite direction to the direction at which the tube is to be rotated. For example, rotating the sleeve 68 downward in
While the first connector 18 is in the released state, the light assembly housing 12 can be rotated with respect to the contact cap 54 to aim the LED's 26 in the proper direction. Engagement of the electrical terminals 22 with the light fixture socket 21 holds the contact cap in a fixed position while the light assembly housing is rotated to aim the LED's.
Once the light assembly housing 12 has been positioned to direct light as desired, the installer loosens the grip on the release sleeve 68, allowing that release sleeve to return to the original relaxed state in which both torsion springs 42 and 44 again firmly engage the grooves 34 and 35 of the rotary fitting 28. This engagement holds the orientation of the housing 12 with respect to the contact cap 54 and the light fixture socket 21 so that the LED's 26 emit light in the desired direction.
To change the orientation of the housing 12 so that the light is directed more downward, the installer rotates the release sleeve 68 in the upward direction. This movement of the release sleeve 68 loosens the second torsion spring 44 in a similar manner to that just described with respect to the opposite motion relaxing the first torsion spring 42. Once the second torsion spring 44 has been relaxed, the light assembly housing 12 can be rotated downward. Once properly aimed, the installer loosens the grip on the release sleeve 68, allowing the second torsion spring 44 to again tighten around the cylindrical section 32 of the rotary fitting 28, thereby holding the housing 12 in the new position.
Depending upon the amount of spring force required to secure the light assembly housing 12 with respect to the contact cap 54, a single torsion spring in the swivel connector 18 may be sufficient. Should a greater amount of force be required than can be provided by two torsion springs, the holding mechanism with torsion springs also can be incorporated in the second swivel connector 20 of the first lighting assembly 10.
With reference to
One of the swivel connectors 112 is shown in detail in the drawings. The swivel connector 112 has a rotary fitting 114 with a socket-like base 116 into which an end of the housing 102 fits and is secured thereto. A tubular, cylindrical portion 118 of the rotary fitting 114 projects from the base 116 away from the housing. The cylindrical portion 118 has an annular flange 120 extending there around thereby forming a groove 122 at the end of the cylindrical section that abuts the base 116. The remote end 130 of the cylindrical portion 118 has an enlarged portion 124 with a semicircular, arcuate notch 126 therein extending between a pair of walls which act as stops 128.
The swivel connector 112 further includes a contact cap 134 formed by a circular base plate 136 from which five fingers 138 project toward the housing. The fingers 138 are equidistantly spaced around the perimeter of the base plate 136 defining a space into which the cylindrical portion 118 of the rotary fitting 114 extends. The ends of the fingers 138, that are remote from the base plate 136 have inwardly projecting teeth 140, enter the rotary fitting's groove 122 thereby securing the those components together. As shown in
A pair of arcuate walls 141 project from the base plate 136 within the array of fingers 138 and extend into the central opening in the exposed end of the rotary fitting's cylindrical portion 118. The arcuate walls 141 guide rotational motion between the rotary fitting 114 and the contact cap 134, as will be described. A tab 142 projects from the base plate 136 between two of the fingers 138. In the assembled swivel connector 112, the tab 142 extends into the arcuate notch 126 at one end of the cylindrical portion 118 of the rotary fitting 114. When the rotary fitting and contact cap rotate with respect to each other, the tab 142 strikes the two stops 128 to limit rotation of the swivel connector to approximately 180 degrees. This prevents excessive twisting of electrical wires (not shown) that extend through the swivel connector 112 between the electrical terminals 132 and the printed circuit board 106.
A tubular release sleeve 146 extends over the contact cap 134. Each of the fingers 138 has an exterior notch 135, all of which are aligned in a circle around the contact cap. The interior surface 148 of the release sleeve 146 has an inwardly projecting annular rib 150. The release sleeve 146 can slide longitudinally along the contact cap 134 into positions in which the interior rib 150 nests in the finger notches 135 and is outside the notched pressing the fingers 138 toward each other.
The second swivel connector 112 can be rotated at the end of the housing 102 so that the light emitted by the LED's 108 and directed through the transparent front portion 110 is emitted in the proper direction regardless of how the electrical terminals 132 are positioned within the light fixture sockets 21, 23. This rotation is accomplished by sliding the release sleeve 146 longitudinally so that the internal rib 150 enters the notches 135 in the fingers 138 of the contact cap. The interior rib 150 nesting within the notches 135 allows the fingers 138 to spring away from the rotary fitting 114. This reduces the friction between those components permitting rotation of the housing 102 and the LED's therein with respect to the contact cap 134 and the light fixture sockets 21, 23.
After the LED's have been properly aimed, the release sleeve 146 is slid against wall 115 of the rotary fitting 114. This action causes the interior rib 150 inside the release sleeve to ride out of the notches 135 and press the fingers 138 radially inward against the rotary fitting 114. This engagement of the rotary fitting by the fingers secures the rotational orientation of the housing 102 and the LED's therein with respect to the contact cap 134 and the light fixture.
The foregoing description was primarily directed to a preferred embodiment of the invention. Although some attention was given to various alternatives within the scope of the invention, it is anticipated that one skilled in the art will likely realize additional alternatives that are now apparent from disclosure of embodiments of the invention. Accordingly, the scope of the invention should be determined from the following claims and not limited by the above disclosure.
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