Abstract:
A fluorescent lampholder with a top portion for supporting a fluorescent lamp and a base portion with a wire opening located on the bottom surface of the base that receives wires without exposing the wires to the exterior surface of a fixture. The lampholder is capable of supporting various types and/or sizes of fluorescent lamps such as “tall”, “medium” and “small” T-8 fluorescent lamps as well as other types and/or sizes of fluorescent lamps.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
   This application claims the benefit of U.S. Provisional Application No. 60/717,081, filed on Sep. 13, 2005. 

   FIELD OF THE INVENTION 
   This invention relates to a fluorescent lampholder, and more particularly to a lampholder for a fluorescent tube of the type comprising an elongate glass envelope having a pair of parallel contact pins at each end. 
   BACKGROUND OF THE INVENTION 
   As is well known, conventional fluorescent fixtures comprise an elongate frame which may include an integral reflector. At each end of the frame there is provided a lampholder for receiving the contact pins at the ends of the fluorescent lamp; the lampholder functions to support the lamp and provide electrical power. The lampholder has a top portion with a pair of spaced apart lamp pin contacts to engage the contact pins of the fluorescent lamp and a base portion with a wire opening located on the side surface of the base portion. During installation, wires are inserted through the wire openings of the lampholders and the wires are electrically connected to the lamp pin contacts of the lampholders to provide electrical power to the lamp. One wired lampholder is mounted at one end of a fixture and another lampholder is mounted at the other end of the fixture. A portion of the wires connected to the lampholder assemblies is typically exposed on the exterior surface of the fixture. There is a need for a fluorescent lampholder that connects to wires without exposing the wires to the exterior surface of the fixture. 
   SUMMARY OF THE INVENTION 
   In accordance with the present invention, a fluorescent lampholder is provided having a body having an upper portion and a lower portion; the lower portion has a bottom surface with an opening formed therein for receiving a conductor, and the upper portion has an opening for receiving lamp pins of a fluorescent lamp. The lampholder also includes an electrically conductive lamp pin contact positioned within the lower portion so that it electrically connects the received conductor and the received lamp pin. According to one aspect of the invention, the lamp pin contact includes a pair of spaced apart contact members, each of the contact members having a surface with an edge and a notch formed in the edge. Upon placement of the lamp in the lampholder, the lamp pins make contact with the edges of the contact members as they engage with the notches. According to another aspect of the invention, each of the lamp pin contact members has a surface with a notch formed therein, and the lamp pins upon placement of the lamp in the lampholder are parallel to those surfaces. 
   According to a further aspect of the invention, the body of the lampholder includes a channel formed therein separating the upper portion and the lower portion; the channel is configured to slidably engage a plate of a mounting fixture so that the bottom surface faces an interior of the fixture and the upper portion is exterior to the fixture. The lampholder thus communicates with the interior of the fixture through the opening, thereby providing a path for the conductor from the bottom surface into the interior of the fixture and isolated from the exterior of the fixture. 
   The lampholder is to supporting various types and/or sizes of fluorescent lamps. The lampholder is available in “tall,” “medium” and “short” versions for T-8 fluorescent lamps as well as other types and/or sizes of fluorescent lamps. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other aspects, features, and advantages of the present invention will become more fully apparent from the following detailed description, the appended claims and the accompanying drawings, in which similar elements are given similar reference numerals. 
       FIG. 1  is an exploded perspective view of a fluorescent lampholder in accordance with an embodiment of the invention. 
       FIGS. 2 ,  3  and  4  are assembled side, front and bottom views respectively of the fluorescent lampholder of  FIG. 1 . 
       FIG. 5  is a partially assembled perspective view of the fluorescent lampholder of  FIG. 1 , showing the cover and lamp pin contacts. 
       FIG. 6  is an assembled perspective front view of the fluorescent lampholder of  FIG. 1 . 
       FIG. 7A  is a schematic illustration of an installation of a fluorescent lamp and lampholder in a fixture, according to the invention. 
       FIG. 7B  is a detail illustration of rotation of a fluorescent lamp to engage electrical contacts of a lampholder in accordance with the invention. 
       FIGS. 8 ,  9  and  10  are assemble side, front and bottom views respectively of a fluorescent lampholder having a single set of wire openings, in accordance with the invention. 
       FIG. 11  is a partially assembled perspective view of a fluorescent lampholder according to the invention, showing a cover and lamp pin contacts thereof. 
       FIG. 12  is an assembled perspective view of a bottom portion of the lampholder of  FIG. 11 . 
       FIGS. 13 and 14  are assembled side and front views, respectively, of the lampholder of  FIGS. 11 and 12 . 
       FIG. 15  is an assembled bottom view of the lampholder of  FIGS. 11-14 . 
       FIG. 16  is an assembled bottom view of a lampholder having only a single set of wire openings, in accordance with a further embodiment of the invention. 
       FIG. 17  is an exploded perspective view of a fluorescent lampholder in accordance with still another embodiment of the invention. 
       FIG. 18  is an assembled front perspective view of the fluorescent lampholder of  FIG. 17 . 
       FIG. 19  is a cutaway view of the interior of the fluorescent lampholder of  FIG. 17 . 
       FIG. 20  is a partially assembled perspective view of the fluorescent lampholder of  FIG. 17 . 
       FIG. 21  is a detailed view of the base of the lampholder of  FIG. 17 . 
   

   DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     FIG. 1  shows a fluorescent lampholder  200  according to a first embodiment of the present invention. The lampholder includes a base  202 , a rotatable cap  204 , a cover  206  and a pair of spaced apart lamp pin contacts  208 . The base  202  has a pair of dual wire openings  212  extending through the bottom surface  211  of the bottom portion  210  of the base for receiving a pair of wires from a power source. The base  202  also has a lamp receiving portion  214  located at the top portion of the base for receiving the pins of a fluorescent lamp. The lamp pin contacts  208  each have a wire contact end  216  and a lamp pin contact end  218 . Each wire contact end  216  has a pair of spaced apart openings  222  to make electrical contact with the bared end of wires from the power source. As shown in  FIG. 1 , the wire contact end may be folded on itself to form a clip adjacent the openings, so that the bared end of an insulated wire urged through the opening is held by the clip, thereby electrically connecting the power source and lamp pin contact  208 . The openings  222  may also be tapered so as to form a one-way clutch permitting insertion of a bared end of an insulated wire but preventing removal of the wire, while making electrical contact with the bare wire ends. Each lamp pin contact end  218  has a notch  220  formed in an edge thereof, to engage one of the two conductive pins of a fluorescent lamp. 
   The lamp receiving portion of the base has an entry slot  224  extending from the top exterior of the base to the interior of the base and a circular central opening  226  in the front face. The cover  206  has an interior circular shaped wall  234  aligned with the central opening  226 , and a top slot  236  and a bottom slot  238  aligned with the entry slot  224 . The cap  204  is formed from a circular shaped disc  240  sized to fit and align with the central opening  226 . A slot  242  extends through the disc for receiving the pins of a fluorescent lamp. The cap  204  has a centrally located hub  244  on the interior surface of the disc; hub  244  is sized to rotatably fit within the circular shaped wall  234 . Ribs  250  located around the hub  244  are used to deflect the lamp pin contacts  208  when the cap  204  is rotated during installation of a fluorescent lamp. 
   The lamp pin contacts  208  are mounted to the interior surface of the cover  206 , with the wire contact end  216  oriented toward the base bottom portion  210  and the pin contact end  218  oriented toward the lamp receiving portion  214 . The cover  206  covers the back of the base  202  and is held in place using tabs  246  which mate with corresponding notches  248  in the base. A pair of channels  230  for mounting the base  202  to a fixture are formed on each side of the base  202 , between the top surface  213  of the bottom portion  210  and tabs  232 . The lampholder may be mounted by sliding the lampholder into a cutout portion of a plate so that the edges of the cutout fit into channels  230 ; the edges are covered by tabs  232  (see  FIGS. 2 and 3 ). Bottom surface  211 , including wire openings  212 , is thus on the underside of the plate (see  FIG. 4 ). Accordingly, wires connected to the lampholder are not visible from the top side of the plate. 
   The base  202 , cap  204  and cover  206  are fabricated from insulating materials such as thermosetting or thermoplastic materials, Bakelite or the like. The lamp pin contacts  208  are fabricated from electrically conducting material such as copper, brass, or the like, or a combination thereof. 
   To make electrical connection between the lampholder  200  and a power source, the bared end of a wire is inserted into one of the dual openings  212  in the bottom surface  211  of the bottom portion of the base, and then urged into the corresponding opening  222  of lamp pin contact  208  (see  FIG. 5 ) until pin contact  208  makes electrical contact with and grips the bared end of the wire. It should be noted that a second wire can be connected to the other of the dual openings  222  depending on the application. For example, both of the dual openings  222  of a contact  208  would be used in a daisy-chain wiring of multiple lampholders. The power source may include standard fluorescent lamp power components such as a ballast and a starter, as is understood by those skilled in the art. 
     FIG. 5  also shows details of the tabs  246  used to secure the cover  206  to the base  202 . In this embodiment, there are three tabs formed integrally with the cover, two near the top end of the cover and one near the bottom end.  FIG. 6  shows the assembled lampholder  200  with the slot  242  in cap  204  aligned with slot  224 , so as to receive the pins of a fluorescent lamp. 
   Once the lampholder  200  has been wired, the wired lampholder is mounted to a fixture  50  such as a housing, at the ends of a reflector  55  or other similar mounting (see  FIG. 7A ). In one embodiment, the lampholder  200  is mounted to a housing made of relatively thin metal plates having an exterior surface  51  and an interior surface  52 . The wired lampholder  200  is slidably mounted onto an opening at an end of a plate  53  so that the plate rests in mounting channels  230 . A second lampholder is mounted at the other end of the fixture in a similar manner. A power supply  60  is located inside the housing, with wires  61  connecting to the lampholders. In this and other embodiments described below, the bottom surface  211  of the base faces the interior of fixture  50 , and the openings  212  in the bottom surface communicate with the interior of the fixture. Accordingly, the lampholders provide a wiring connection path such that the wires extend from the bottom surface  211  of the base into the interior, preventing the wires from being exposed to the exterior surface of the housing. The lampholders are thus mounted to the exterior of fixture  50  while the wires  61  are hidden within the interior. This offers a number of advantages, including an improved electrical wiring connection, a more pleasing appearance and a reduction in the cost of manufacture. 
   Once the lampholders are mounted to the fixture, a fluorescent lamp  10  is attached to the lampholders as described below. The fluorescent lamp is turned so that its pins at one end are positioned one above the other; the lamp pins are made to enter a channel formed by slot  224  of the base and slot  242  of the cap (as shown in  FIG. 6 ). Once the lamp pins are aligned in the channel, the lamp is rotated until each of the lamp pins enters notch  220  of its associated lamp pin contact  208 . The tapered lead-ins to each of the notches from above and below assure that the lamp pins enter the notches. The resilience and shape of the pin contact end allows it to first be deflected as the lamp pins move into position in the notches  220 , and then return to grip the lamp pins once they are seated in their associated notches  220 . It is noteworthy that lamp pin contact ends  218  are flat, with notches  220  formed in the inside edges thereof (see  FIGS. 1 and 5 ). Referring to  FIG. 7B , when the lamp  10  is rotated in a direction S to engage pins  11  in the notches  220 , the axis of rotation Z of the lamp is normal to the flat surfaces of contact ends  218 . A lamp pin being moved against contact  208  thus slides along the edge of the contact until it engages with notch  220 . This is sometimes referred to as an “edge wipe” contact between the lamp pin and the lampholder. 
     FIGS. 8-10  show a fluorescent lampholder  280  in accordance with another embodiment. The lampholder  280  is similar to the lampholder  200  except that the lampholder  280  has only one set of wire openings  282 , whereas lampholder  200  has a pair of dual wire openings  212 . The lampholder  280  is for use with a fluorescent lamp that has two pins for mechanical support, but where only one pin is necessary to deliver power to the lamp. To accommodate such a lamp, a shunt (not shown) is placed across the lamp pin contacts to electrically couple the contacts together, thereby effectively providing power from a single contact. Since only one contact is required, only a single set of wire openings is needed; the other set of wire openings is closed by a cover  283 , as shown in  FIG. 10 . 
     FIGS. 11-15  show a fluorescent lampholder  300  in accordance with still another embodiment of the invention. Lampholder  300  is similar in construction and operation to lampholder  200  except that the lampholder  300  is sized to support a smaller fluorescent lamp (compare  FIGS. 13 and 14  with  FIGS. 2 and 3  respectively). Lampholder  300  includes lamp pin contacts  308  and has dual wire openings  312  for making wiring connections to the lamp pin contacts (see  FIGS. 11 and 12 ). As described above with reference to the first embodiment, lampholder  300  has two pairs of dual wire openings  312 . In a further embodiment, lampholder  380  is similar to lampholder  300  except that the lampholder  380  has only one set of wire openings  382 . lampholder  380  is for use with a fluorescent lamp that has two pins for mechanical support, but where only one pin is necessary to deliver power to the lamp. To accommodate such a lamp, a shunt (not shown) is placed across the lamp pin contacts to electrically couple the contacts together, thereby effectively providing power from a single contact. Since only one contact is required, only a single set of wire openings is needed; the other set of wire openings is closed by a cover  383 , as shown in  FIG. 16 . 
     FIG. 17  is an exploded perspective view of a fluorescent lampholder  400  in accordance with still another embodiment of the invention. Lampholder  400  includes a base  402 , a rotatable cap  404 , a lamp receiving portion  414  and a pair of spaced apart lamp pin contacts  408 . The base  402  has a pair of dual wire openings  412  extending through the bottom surface  411  for receiving a pair of wires from a power source, and a top surface  413  for supporting the contacts  408 . A pair of channels  430  for mounting to a fixture are formed on each side of the base  402  located between the top surface  413  of the base and flat, rectangular shaped tabs  432 . Unlike the angled tabs  232  of the lampholder  200  (compare  FIG. 3 ), the flat tabs  432  of lampholder  400  reduce the need for additional “camming” during the molding process of manufacture. 
   The lamp pin contacts  408  each have a wire contact end  416  with a pair of tapered openings  422  to make electrical contact with the bared end of wires from a power source, and a pin contact end  418  with a notch  420  to engage one of the two conductive pins of a fluorescent lamp. The tapered openings  422  function as a one-way clutch that allows the bared end of an insulated wire to be inserted but prevents the removal of the wire while making electrical contact with the bare wire ends. Unlike the lampholder  200  described above, in which the lamp pins of a lamp make contact with the edge of the lamp pin contacts  208 , contacts  408  make contact with the lamp pins at notches  420  located on the front surface of the contacts. A fluorescent lamp placed in lampholder  400  therefore has the lamp pins thereof parallel to the front surfaces of the contacts, with the pins resting in the notches  420 . 
   The lamp receiving portion  414  has an entry slot  424  extending from the top exterior of the lamp receiving portion to the interior thereof and a circular central opening  426  in the front face. The cap  404  is formed from two spaced apart circular shaped discs  440 ,  441  with a centrally located hub portion  444  connecting the discs. The discs are sized so that cap  404  fits rotatably within the circular opening  426 . The cap  404  has a slot  442  extending through the exterior surface of the exterior disc; the cap  404  is rotated so that this slot and the slot is capable of being aligned with the slot  424  of the cover to receive the pins of a fluorescent lamp. Protrusions  450  extending from the side of the centrally located hub portion  444  are adapted to make contact with notches  420  on the lamp pin contacts  408 , and deflect the lamp pin contacts  408  when the cap  404  is rotated during the installation of a fluorescent lamp (see  FIG. 19 ). 
   The wire contact end  416  of each lamp pin contact  408  is mounted onto the top portion of the base for receiving wires, and the pin contact end  418  extends into the interior of lamp receiving portion  414  for receiving the pins of a fluorescent lamp. Lamp receiving portion  414  is secured to base  402  and is held in place by tabs  446  on the base which mate with corresponding notches  448  in the lamp receiving portion (see  FIGS. 18 and 19 ). A shunt  460  is mounted onto the base to electrically connect the two pins  408  together (see  FIG. 21 ). 
   The lampholder  400  components are fabricated from materials similar to the lampholder  200  above. Lampholder  400  is likewise wired and mounted as described above with reference to lampholder  200 . 
   While the invention has been described in terms of specific embodiments, it is evident in view of the foregoing description that numerous alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, the invention is intended to encompass all such alternatives, modifications and variations which fall within the scope and spirit of the invention and the following claims.