Patent Publication Number: US-8109646-B2

Title: Self-centering pull-out light tube assembly

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of priority under 35 USC 119 of U.S. provisional application No. 61/082,121, filed on Jul. 18, 2008. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a pull-out light tube assembly for an equipment rack or other assembly, and more particularly to a pull-out light tube assembly with a mechanism for self-centering on retraction. 
     2. Description of Related Art 
     Pull-out light tube assemblies have been provided for assemblies such as rack-mount systems for audio and video equipment. The light tube assembly includes a light tube that can be pulled out of, and retracted into, a bushing or holder formed in a front panel of an equipment or component mounted in the rack. A lamp or bulb is mounted inside of the light tube, and the light tube includes at one end (the pulled out end) a light opening through which light from the lamp shines in order to illuminate portions of surrounding equipment in the rack. 
     In one configuration, the light opening is provided in a lower portion of the light tube, and the light tube is rotatable within the bushing so that light can be shined on a desired part of the equipment rack. Thus, when pulled out, light can be shined through the light opening to illuminate equipment directly below the light tube, or the light tube can be rotated to aim the light opening in order to illuminate equipment to the sides of the light tube. When no longer needed, the light tube is pushed back into the bushing. 
     A manufacturer or decorative logo, such as a letter or a symbol, may be provided at a front end of the light tube in order to improve the ornamental appearance and design of the light tube when retracted into the bushing, and/or to designate the manufacturer of the light tube assembly. However, when known light tubes are pulled out from the bushing and rotated, and then pushed back or retracted into the bushing without being rotated back to the original position, the logo at the front end of the light tube will remain at a rotated and off-center position, thereby not being properly oriented and detracting from the appearance of the light tube assembly and equipment rack in which it is installed. At present, the only known method for returning the light tube assembly to a centered and more visually appealing position is by manual rotation of the light tube back to its centered position. However, the user of the light tube may very likely forget or neglect to take this restorative action, thereby leaving the light tube assembly in an improperly oriented and visually less appealing state. 
     SUMMARY OF THE INVENTION 
     The present invention addresses this problem and provides a mechanism for self-centering a pull-out light tube assembly when the light tube is pushed back or retracted into its bushing or holder. 
     In particular, the present invention provides a pull-out light tube assembly that can be mounted in an equipment component such as a component that is mounted in an equipment rack. The light tube assembly includes a light tube received within a bushing. The light tube can be pulled out from the bushing and retracted into the bushing. The assembly includes a mechanism for self-centering the light tube within the bushing when the light tube is retracted into the bushing. 
     In one embodiment of the invention, a guide pathway formed in the bushing receives and guides a guide pin formed in the light tube to a centered position. The guide pathway may be a V-shaped groove with a receptacle and detent formed at an end thereof to secure the guide pin in a centered position. 
     In one embodiment of the invention, the mechanism for self-centering maintains a logo formed at a front end of the light tube in a properly oriented position when the light tube is retracted within the bushing. 
     Other features and advantages of the invention will be apparent from the following detailed description, taken in conjunction with the accompanying drawings that illustrate, by way of example, various features of embodiments of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front view of equipment having a pull-out light tube assembly in a retracted state, according to the present invention. 
         FIG. 2  is a top view of the equipment of  FIG. 1 , with the light tube assembly in the retracted state. 
         FIG. 3  is a top view of the equipment of  FIG. 1 , with the light tube assembly in an extended state. 
         FIG. 4  is a bottom view of the equipment of  FIG. 1 , showing the light tube assembly in the extended state and light openings formed in the light tubes. 
         FIG. 5  is a front view of the equipment of  FIG. 1 , with the light tube assembly in the retracted state, as installed in an exemplary rack of equipment. 
         FIG. 6  is a top view of the rack of equipment of  FIG. 5 , with the light tube assembly in the retracted state. 
         FIG. 7  is a top view of the rack of equipment of  FIG. 5 , with the light tube assembly in the extended state. 
         FIG. 8  is a top view of an assembled light tube assembly, including a light tube and a bushing, according to the present invention. 
         FIG. 9  is a top view of a disassembled light tube assembly, including the light tube and bushing. 
         FIG. 10  is a perspective view of the light tube assembly in a retracted and centered position. 
         FIG. 11  is a view of the retracted and centered light tube assembly of  FIG. 10 , showing positioning of a guide pin formed on the light tube at an end of a guide pathway formed in the bushing. 
         FIG. 12  is a perspective view of the light tube assembly in an extended and rotated position. 
         FIG. 13  is a view of the extended and rotated light tube assembly of  FIG. 12 , showing the guide pin formed on the light tube and the guide pathway formed in the bushing. 
         FIG. 14  is a side view of the light tube including the guide pin. 
         FIG. 15  is a side view of the light tube assembly, including the light tube with the guide pin and the bushing with the guide pathway. 
         FIG. 16  is a side view of the light tube assembly, showing retraction of the light tube. 
         FIG. 17  is a side view of the light tube assembly, showing retraction of the light tube to a near-centered position. 
         FIG. 18  is a side view of the light tube assembly, showing retraction of the light tube to a fully-centered position. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIGS. 1-4  illustrate an exemplary component or piece of equipment  10  having a pull-out light tube assembly  12  installed therein according to the present invention. Equipment or component  10  may be, for example, audio or video equipment configured to be mounted within an equipment rack. While equipment  10  is illustrated as having two pull-out light tube assemblies installed therein, it may have any other number of light tube assemblies installed therein. 
     As illustrated in  FIGS. 8-18 , and as will be described in more detail herein, pull-out light tube assembly  12  is formed by a light tube  20  that is extendable from and retractable into a bushing or holder  30  that is mounted to a front panel of equipment  10 . Light tube  20  may be retracted or pushed into bushing  30  when not in use, and may be extended or pulled out from bushing  30  when in use.  FIGS. 1 and 2  illustrate light tube assembly  12  in a retracted position, and  FIGS. 3 and 4  illustrate light tube assembly  12  in an extended position. 
     A decorative logo or symbol  14  is formed on a front end of light tube assembly  12 . The front end of light tube assembly  12  on which logo  14  is formed may be, for example, a removable cap at the end of light tube  20 , thereby facilitating exchange of the light bulb mounted therein. Alternatively, the front end of light tube assembly  12  on which logo  14  is formed may be an integral and non-removable part of light tube  20 . As depicted in the drawings, logo  14  comprises the letter “F”. However, logo or symbol  14  may be any desired or appropriate logo, symbol, letter or other marking. As will be described in more detail herein, light tube assembly  12  includes a mechanism for self-centering during retraction, thereby maintaining a centered and properly oriented appearance of logo  14  when retracted. 
     A lamp or bulb is mounted inside of light tube assembly  12 . As shown in  FIG. 4 , a light opening  16  through which light from the internally-mounted lamp shines is formed at one end (the pulled out end) of light tube  20 . As illustrated, light opening  16  is formed in a lower or bottom portion of light tube  20 . However, light opening  16  may be formed in any desired part of light tube  20 . 
     Light tube  20  is rotatable within bushing  30  so that light can be shined on a desired part of the equipment rack. Thus, when pulled out, light can be shined through light opening  16  to illuminate equipment directly below light tube assembly  12 , or light tube  20  can be rotated within bushing  30  to aim light opening  16  in order to illuminate equipment to the sides of light tube assembly  12 . When no longer in use, light tube  20  is pushed back into bushing  30 . 
     As previously mentioned, the equipment or component  10  in which light tube assembly  12  is mounted is typically installed in an equipment rack or system.  FIGS. 5-7  show equipment  10  with light tube assembly  12  installed therein as mounted in a rack  18 .  FIGS. 5 and 6  show light tube assembly  12  in a retracted position, whereas  FIG. 7  shows light tube assembly  12  in an extended position such that light can be shined from light tube assembly  12  in order to illuminate portions of rack  18  below equipment  10 . 
     As previously mentioned, and illustrated in  FIGS. 8 and 9 , each light tube assembly  12  includes a light tube  20  that is received within a bushing  30 . Light tube  20  is movable within bushing  30 , such that it may be extended (pulled-out) from or retracted (pushed-in) into equipment  10 . Light tube  20  is also rotatable within bushing  30 , such that the position of light opening  16  may be manipulated to shine light as desired. As such, to facilitate rotation, light tube  20  and bushing  30  preferably have a mating, cylindrical shape. 
     As shown, for example, in  FIGS. 10 and 12 , logo  14  is formed at a front end  15  of light tube  20 .  FIG. 10  shows light tube  20  retracted into bushing  30  and centered, whereas  FIG. 12  shows light tube  20  pulled out from bushing  30  and rotated, such that logo  14  is off-center and is tilted and improperly oriented. As will now be discussed in detail, pull-out light tube assembly  12  includes a self-centering mechanism such that light tube assembly  12  is returned to a centered position when retracted into bushing  30 , such that logo  14  remains properly oriented and upright, and maintains a consistent and visually appealing appearance. 
     As shown in FIGS.  11  and  13 - 15 , light tube  20  has a guide pin or knob  22  formed on a lower surface thereof. Bushing  30  has a guide channel or pathway  32 , in the form of a V-shaped groove, that receives and guides pin  22  towards a centered position when light tube  20  is pushed into bushing  30 . In a fully retracted and centered position ( FIG. 11 ), pin  22  fits within a receptacle or slot  34  formed at the end of V-shaped groove  32 , such that light tube  20  is centered and cannot be rotated until light tube  20  is pulled out from bushing  30  ( FIG. 13 ), thereby removing pin  22  from receptacle  34  and allowing light tube  20  to rotate within bushing  30 . As can be seen in  FIG. 13 , retention detents  36  may be formed in receptacle  34  of pathway  32  in order to retain tube  20  in a centered position until force is exerted to pull out tube  20 . 
       FIGS. 16-18  illustrate the self-centering interaction of guide pin  22  and guide pathway  32  as light tube  20  is pushed or retracted into bushing  30 . As tube  20  is pushed in, guide pin  22  contacts V-groove or channel  32 , thereby interfering with and constricting the range of rotation of tube  20  within bushing  30  ( FIG. 16 ). As light tube  20  is pushed further in ( FIG. 17 ), guide pin  22  arrives at the end of V-groove  32  and begins to enter the slot or receptacle  34  formed at the end of V-groove  32 . In  FIG. 17 , light tube  20  is almost fully pushed into bushing  30 , and is almost fully-centered.  FIG. 18  shows light tube  20  in a fully-centered position within bushing  30 . Guide pin  22  is pushed completely into slot or receptacle  34 , and is held therein by detents  36 , such that a minimal pull-out force must be exerted in order to move light tube  20  from its fully-centered position. 
     The configuration of pull-out light tube assembly  12 , as shown and described herein, represents a significant improvement over prior art assemblies. When previously known light tubes are pulled out from their bushings and rotated, and are then pushed back or retracted into the bushing without being rotated back to the original position, there is no mechanism other than manual rotation to re-center the light tube within the bushing. Thus the logo at the front end of the light tube will remain at a rotated and improperly oriented position, thereby detracting from the appearance of the light tube assembly and equipment rack in which it is installed. The user of the light tube will very likely forget or neglect to re-center the light tube, thereby leaving the light tube assembly in an off-centered and visually less appealing state. The present invention overcomes this problem by providing the above-described mechanism that self-centers the light tube within the bushing whenever the light tube is pushed back or retracted into the bushing, such that the front logo is always maintained in a properly oriented, upright and visually appealing state. 
     While particular embodiments of the invention have been described, it should be understood that these embodiments are exemplary, and not restrictive. Various modifications will be apparent to those of skill in the art and are within the scope of the present invention as set forth in the following claims.