Patent Publication Number: US-7214105-B1

Title: Light socket housing

Description:
FIELD OF THE INVENTION 
   The present invention relates generally to light bulb sockets and more specifically to a housing that is suitable for use with a standard light socket. 
   BACKGROUND 
   The standard light socket is a basic fixture in virtually every home and office. These are commonly used in standing floor lamps, light fixtures as well as in table-top or desk-top lamps. One popular design has a metal casing that holds the actual light socket. The metal casing consists of two parts: a shell and a cap. The shell is substantially tubular and the cap is shaped in the form of a cup that covers the bottom of the shell. The light socket is positioned inside of the shell. The cap is placed over the end. The shell and cap are crimped so that when pressed together they snap into place. 
   SUMMARY OF THE INVENTION 
   According to one aspect of the invention, a housing for a standard electric light socket has a base, a body and a ring nut. The base is formed from a pressed metal cup and a round metal nut. The metal cup has a wide top defining a rim and a narrow bottom defining a hole. The pressed metal cup defines a shoulder positioned between the wide top and the narrow bottom. A side wall of the metal cup is substantially vertical from the rim to the first shoulder, then narrows at the first shoulder to form a bevel along an outer surface of the first side wall, and then curves inward toward the narrow bottom of the metal cup. The side wall defines a first slot extending down from the rim. The round metal nut is a substantially hollow cylinder having a top and a bottom. The substantially hollow cylinder has threads through its hollow interior from the top to the bottom. A pair of flanges extend up from the top of the substantially hollow cylinder and pass through the hole in the narrow bottom of the pressed metal cup. The flanges are pressed apart to attach the round metal nut to the pressed metal cup. The body has a substantially cylindrical shape and is also formed of pressed metal. The body has a round top, a round bottom, a shoulder approximately midway between the round top and the round bottom and a band of threads proximate the round bottom. A side wall formed from a single piece of pressed metal extends from the round top to the round bottom of the body. A portion of the second side wall extending from the round top to the second shoulder is substantially vertical. The side wall widens at the second shoulder. A portion of the side wall extending from the shoulder to the band of threads is substantially vertical. The side wall widens at the band of threads so that an inner diameter of the body taken at the band of threads is greater than an outer diameter of the base taken at the rim. An inner diameter of the body taken above the band of threads and below the second shoulder is less than or equal to the outer diameter of the base taken at the rim. The body further defines a vertical slot extending from the round bottom through the band of threads and through a portion of the side wall below the shoulder. A dimple is punched inward through the band of threads. When the body is placed over the base so that the band of threads on the body substantially surround a portion of the base from the rim to the shoulder. The dimple in the body aligns with and engages the slot in the base so that the band of threads is prevented from turning around the portion of the base from the rim to the shoulder. The ring nut has a top and a bottom and a threaded interior wall extending from the top to the bottom. The top and the threaded interior wall are sized to engage the band of threads on the body. The bottom narrows so that a diameter taken across a hole defined by the bottom of the ring nut is less than a diameter taken across the rim of the base. When the ring nut engages the band of threads on the body and is tightened, the bottom of the ring nut presses upward against the shoulder of the base so that the rim of the base presses up against the portion of the side wall of the body extending from the shoulder to the band of threads. 
   According to further aspects of the invention, a standard socket assembly includes an insulated base, a threaded metal socket and a switch mechanism. The insulated base fits within the body below the second shoulder. The threaded metal socket fits within the body above the second shoulder. The switch mechanism extends out through the vertical slot in the body. An insulating cardboard tube is positioned between the standard socket assembly and the body. 
   According to another aspect of the invention, a housing especially suited for a standard light bulb socket includes a shell, a cap and a capture ring. The shell has a substantially cylindrical shape. The shell has an upper portion, a lower portion below the upper portion and a threaded portion below the lower portion. The upper portion has a first inner diameter. The lower portion has a second inner diameter larger than the first inner diameter. The treaded portion has a third inner diameter larger than the second inner diameter. The shell defines a slot extending through the threaded portion and into the lower portion. The cap has a circular band extending around its top, a cup extending down from the circular band, and a nut attached to a bottom of the cup. The circular band has a first outer diameter that is less than or equal to the third inner diameter. The cup has a second outer diameter that is less than the first outer diameter so that the circular band and cup form a shoulder as they meet. The capture ring has a threaded interior wall sized to engage the threaded portion of the shell. The capture ring has a lip extending inward at its bottom to define an aperture having a forth inner diameter larger than the second outer diameter but smaller than the first outer diameter. When the threaded interior wall of the capture ring engages the threaded portion of the shell, the aperture presses against the shoulder to secure the cap. 
   According to further aspects of the invention, the shell is constructed from a single sheet of stamped or pressed metal. The cup and circular band of the cap are also formed from another single sheet of pressed metal. The shell has a dimple extending inward from the threaded portion. The circular band of the cap defines a square slot extending downward from its top. The square slot engages the dimple to prevent the shell from rotating with respect to the cap. The bottom of the cup defines a round hole having a pair of nibs extending inward from opposite sides of the round hole. The nut has a substantially cylindrical body with a pair of flanges extending up from a top side of the nut. The flanges extend up through the round hole in the bottom of the cup and are positioned between the nibs on opposite sides of the round hole. The flanges are pressed apart to attach the nut to the cup and wherein the nibs prevent the cup from rotating with respect to the nut. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1A  is a perspective view of a light socket with a turn knob housed within a shell. 
       FIG. 1B  is a perspective view of a light socket with a pull chain housed within a shell. 
       FIG. 2  is an exploded view of the light socket with the turn knob and shell of  FIG. 1A . 
       FIG. 3A  is a perspective view of a front side of a stamped shell used in an assembly for housing a standard light socket. 
       FIG. 3B  is a perspective view of a back side of the stamped shell of  FIG. 3A . 
       FIG. 3C  is an end view of the stamped shell of 
       FIG. 4A  is a side view of a stamped cap used in an assembly for housing a standard light socket. 
       FIG. 4B  is an end view of the stamped cap of  FIG. 4A . 
       FIG. 4C  is an exploded side view of the stamped cap of  FIG. 4A . 
       FIG. 4D  is an exploded end view of the stamped cap of  FIG. 4A . 
       FIG. 5A  is an end view of a captive ring used in an assembly for housing a standard light socket. 
       FIG. 5B  is a cross-sectional side view of the captive ring of  FIG. 5A , taken along section  5 B— 5 B. 
       FIG. 6  is another preferred housing for a standard light socket. 
   

   DETAILED DESCRIPTION 
   A housing for a standard light socket is constructed from three components: a shell, a cap and a captive ring. The shell is made of stamped (or pressed) metal, preferably brass. It is substantially tubular in shape. It has a shoulder midway along its body and is sized to receive a standard light socket interior. These are commercially available from a number of manufacturers. Typically, the interior portion of a light socket is termed the light socket interior. As used herein, however, light socket and light socket interior may be used interchangeably. The shell narrows at the shoulder and the light socket is positioned within the wider portion of the shell. The shoulder prevents the light socket from sliding up through the shell. The bottom of the shell has a band of threads. The shell widens slightly at this band to form another shoulder. The cap is also made of stamped metal but includes a bottom nut that is used for mounting the housing on a threaded tube or hollow stud. The cap covers the bottom of the shell. It has a hollow cup shape that provides space for running wires that connect with the light socket. The top of the cap fits within the band of threads at the bottom of the shell. The shoulder at the top of this band prevents the cap from sliding up further into the shell. The portion of the cap that fits within the shell is wider than the rest of the cap. The captive ring is threaded on its inside and has a flange or shoulder along its bottom so that the maximum inner diameter at the bottom of the captive ring is less than the diameter across the threaded portion. This flange or shoulder at the bottom of the captive ring is used to hold the cap in place. Specifically, the threads in the captive ring engage the threads at the bottom of the shell. When tightened, the flange or shoulder at the bottom of the captive ring presses against the top, wider portion of the cap to hold it in place. 
   Turning to  FIG. 1A , a housing is shown with a standard light socket interior (Leviton no. 7090-M). The housing includes shell  102 , cap  104  and ring  106 . The light socket includes standard components that are further identified below. Component parts of the light socket that are at least partially visible in  FIG. 1A  include a threaded metal band  108 , a cardboard insulator  110  and a turn knob  112 . The treaded metal band  108  receives a standard light bulb. The insulator  110  isolates the threaded metal band  108  from the outer shell  102 . The insulator  110  extends well past the threaded metal band  108  and past the outer shell  102  to prevent the possibility that a user would come in contact with live electricity. The turn knob  112  is used to operate the light socket. 
   Turning to  FIG. 1B , a similar housing is shown with a standard light socket interior (Leviton no. 19980-M). Unlike the socket shown in  FIG. 1A , this one is operated by a pull cord  114 . The housing, however, has the same component parts, including a shell  116 , a cap  118  and a ring  120 . 
   Turning to  FIG. 2 , an exploded view of the housing and standard light socket of  FIG. 1A  are further described. Again, as shown, this includes the shell  102 , cap  104  and ring  106 . It also includes the cardboard insulator  110 , threaded metal band  108  and knob  112 . The treaded metal band  108  and knob  112  are part of a standard light socket assembly  202 . These are commercially available. The light socket assembly is covered below by another cardboard insulator  206 . It has a cup shape and when assembled, the insulator  206  lines the interior of cap  104 . This prevents any bare wire carrying electricity through the cap  104  from coming in contact with the cap  104 . These individual components are now described in further detail. 
   The shell  102  is constructed of stamped metal, preferably brass. It is plated or painted or otherwise finished to match a fixture. The shell  102  is substantially tubular with a round open top and bottom. It has an upper portion  208  that transitions into a lower portion  210  at shoulder  212 . The upper portion  208  has an interior diameter that is slightly smaller than the lower portion  210 . The shoulder  212  between these portions limits the movement of the insulator  110  and socket assembly  202  up into the shell  102 . The bottom of the shell  102  defines a band of threads  214 . This portion of the shell  102  joins the lower portion  210  at a shoulder  216 . The inner diameter of the shell  102  at the band of threads  214  is slightly larger than at the lower portion  210 . The shoulder  216  limits the movement of the cap  104  up into the shell  102 . The shell  102  also defines a slot  218 . This passes through the band of threads  214 , past shoulder  216  and approximately midway up into the lower portion  210 . It is used to pass the shaft of knob  112 . On the back side of the band of threads  214 , a dimple is pressed. This is not visible in this view but is shown in  FIG. 3B  and described below. The dimple extends inward and is used to prevent cap  104  from turning inside shell  102 . 
   The cardboard insulator  110  is also substantially tubular in shape. It has an open top and bottom. It is divided into an upper portion  220  and a lower portion  222 . These are separated by a shoulder  224 . The upper portion  220  has a diameter that is just slightly smaller than that of the lower portion  222 . The outer diameter of the upper portion  220  is sized to fit snugly within the inner diameter of the upper portion  208  of the shell  102 . Likewise, the outer diameter of the lower portion  222  is sized to fit snugly within the inner diameter of the lower portion  210  of shell  102 . The outer diameter of the lower portion  222  of insulator  110  is equal to or slightly greater than the inner diameter of upper portion  208  of shell  102 . Thus, when the insulator  110  is slid inside of the shell  102 , the shoulder  224  on the insulator  110  presses against the shoulder  212  on the shell  102 . The insulator  110  is sized so that it completely covers the interior of the shell  102 . At the top end, the insulator extends slightly beyond the shell  102  (as shown in  FIG. 1A ). At the bottom, insulator  110  extends even with or slightly beyond the bottom of the band of threads  214 . In other words, the upper portion  220  of the insulator  110  is slightly longer than the upper portion  208  of the shell  102  and the lower portion  222  of the insulator  110  is slightly longer than the lower portion  210  of shell  102 . Insulator  110  also defines a slot  226 . It has approximately the same width as the slot  218  in the shell  102 . It is, however, slightly longer because the lower portion  222  of insulator  110  is slightly longer than the lower portion  210  of shell  102 . When the insulator  110  is positioned inside shell  102 , the slot  226  is aligned with slot  218  so that they can pass the shaft of knob  112 . The top end of slot  226  matches with the top end of slot  218 . 
   The light socket assembly  202  includes the threaded metal band  108  and an insulated base  204 , which houses the mechanical switching mechanism. This connects with knob  112 . The insulated base  204  also includes connection points for electrical wiring. These are screw-type connections and a screw head  228  for one such connection is shown. The other connection is on the back side, opposite the knob  112 . The outer diameter of band  108  is equal to or slightly less than the inner diameter of upper portion  220  of insulator  110 . Band  108  fits snugly within the upper portion  220  of insulator  110 . The insulated base  204 , includes a lip  230  extending around its top. The lip  230  is circular and is just slightly wider than the band  108 . The two are concentric. The diameter across the insulated base  204  at this lip  230  is approximately equal to or slightly smaller than the inner diameter of the lower portion  222  of insulator  110 . This diameter, however, is slightly larger than the inner diameter of the upper portion  220  of insulator  110 . Thus, when the light socket assembly  202  is positioned within the insulator, the lip  230  will press up against shoulder  224  and prevent the light socket assembly  202  from sliding further up into the insulator  110 . The shaft of knob  112  is aligned with the slots  218  and  226 . When lip  230  presses against shoulder  224 , the shaft of knob  112  will just touch the top of these slots. The rest of the insulated base  204  is the same or narrower than lip  230 . 
   Below the light socket assembly  202  is the cardboard insulator  206 . It is shaped in the form of a cup with a hole  232  in its bottom. The outer diameter of insulator  206  is approximately the same as that of lip  230 , so that its top edge meets the bottom of the insulated base  204  but is not large enough to fit past the insulated base. Wires connecting with the terminals on insulated base  204  pass through the hole  232 . Insulator  206  is sized to fit snugly within the middle portion  234  of cap  104 . 
   Cap  104  has a top band  236 , a middle portion  234  and a bottom nut  238 . Cap  104  is formed from a pressed or stamped metal, preferably brass and is finished to match shell  102 . The top band  236  has a round shape. It has an inner diameter that is approximately the same as the lower portion  210  of shell  102  and has an outer diameter that fits within the inner diameter of the threaded band  214  of shell  102 . When assembled, band  236  fits inside of threaded band  214  and the top rim of band  236  presses against the shoulder  216 . Band  236  is just slightly wider than threaded band  214  so that it will extend just past the bottom of threaded band  214  when fully in position. The insulator  110 , which extends down past the bottom of threaded band  214  fits inside of band  236 . In other words, band  236  is sandwiched between the bottom of insulator  110  on the inside and threaded band  214  on the outside. Band  236  also defines a square notch  237 . The square notch  237  extends from the top rim of band  236  down but not all the way to the bottom of band  236 . The notch  237  is used to prevent cap  104  from turning with respect to shell  102 . As mentioned above, threaded band  214  has a dimple pressed inward. This dimple is aligned with and extends through notch  237 . When assembled, the dimple is contained by notch  237  so that the two pieces (shell  102  and cap  104 ) cannot rotate with respect to each other. 
   The bottom of band  236  joins the top of cup  234 . The diameter of band  236  is slightly greater than the diameter of cup  234  at its top so that a shoulder  240  is formed where they join. This creates a beveled outer surface. The inner diameter at the top of cup  234  is approximately equal to or slightly less than the inner diameter of the lower portion  222  of insulator  110 . Thus, when the cap  104  is positioned, the inside of shoulder  240  presses against the bottom of insulator  110  to hold it in place. 
   Again, the insulated cup  206  is sized to fit within cap  104 . The top rim of cup  206  is flush on the inside with shoulder  240 . The bottom of cup  234  defines a hole that is used to attach bottom nut  238 . This attachment is further described below with reference to  FIGS. 4A–4D . Bottom nut  238  is cylindrical, with a slightly widened segment at its tip forming a lip  242 . Bottom nut  238  is hollow with threads on its inside. These are used to mount the assembly as part of a lamp or other fixture. 
   Ring  106  is the final piece in the assembly. It is open on both its top and bottom and is threaded on its inside. It is sized so that these threads engage the band of threads  214 . The opening on the bottom of ring  106  is slightly narrower. It is used to capture cap  104 . Specifically, the bottom of ring  106  defines an opening with a diameter that is greater than the outer diameter at the top of cup  234  but smaller than the outer diameter of band  236 . Thus, when it engages the band of threads  214 , it presses against shoulder  240  to hold the entire assembly together and in place. 
   Turning to  FIGS. 3A–3C , the shell  102  is further shown and described. In  FIG. 3A , the shell  102  is shown from a front perspective view. Here, the slot  218  is visible. In  FIG. 3B , the shell  102  is rotated 180 degrees so that the dimple  302 , mentioned above, is visible in the band of threads  214 . It is made by pressing a small, rectangular punch against the band of threads  214 . When viewed from the bottom end of the shell  102 , the dimple  302  extends inward past the inner diameter of the lower portion  210  as well as the upper portion  208 . 
   Turning to  FIGS. 4A–4D , the cap  104  is further described. In  FIGS. 4A and 4B , the cap  104  is shown assembled. In  FIGS. 4C and 4D , the cap is shown in an exploded view. 
   Again, cap  104  consists of a cup  234  and band  236  formed from a single piece of pressed metal. It also has a round nut  238  that attaches to the bottom of cup  234 . The band  236  defines a notch  237  that aligns with the dimple  302  in shell  102  described above. 
   As shown in  FIG. 4C , nut  238  has a substantially cylindrical body that widens at its top to form lip  242 . Lip  242  has a diameter that is wider than the hole through the bottom of cup  234 . Above lip  242  a pair of semi-circular flanges  402  extend in an upward direction. As shown in  FIG. 4D , the semi-circular flanges are concentric with the lip  242 . They follow the rim of lip  242  but are spaced slightly inside of the outer edge of the lip  242 . The semi-circular flanges  402  are separated on each side by a gap  404 . When assembled, the semi-circular flanges  402  extend up through the hole in the bottom of cup  234 . 
   More specifically, the hole  406  in the bottom of cup  234  is shown in  FIG. 4D . It is round, but has a pair of nibs  408  on opposite sides extending inward. As shown in  FIG. 4B , the semi-circular flanges extend up through hole  406 . The nibs  408  are positioned to align with the gap between the two semi-circular flanges  402 . The flanges  402  are then pressed apart to form a solid attachment with the cup  234 . The nibs  408  prevent the nut  238  from turning with respect to the cup  234 . The interior of nut  238  is threaded. In addition, a set screw passes  410  though the middle of nut  238 . When the nut  238  engages a mounting stud, the set screw  410  is tightened to prevent the assembly from turning. 
   Turning to  FIGS. 5A and 5B , a ring  106  is shown in further detail.  FIG. 5B  is a cross section taken along section  5 B— 5 B of  FIG. 5A . As shown, the interior wall  502  of ring  106  is threaded. The bottom of ring  106  defines a flange or lip  504  that extends inward. The lip  504  defines an aperture that is narrower than the rest of the interior of ring  106 . As described above, this is used to engage the shoulder  240  of cap  104 . 
   Turning to  FIG. 6 , another shell assembly  600  is shown. It includes a shell  602 , a cap  604  and a ring  606 . Unlike the previously described shell assemblies, this one does not include a slot to pass a knob or pull chain (Leviton no. 9347-000). The switch must be included as part of the lamp, fixture or installed wiring. Because, the socket assembly does not include a built-in switch, it will be smaller. Accordingly, the lower portion  608  of the shell  602  is shorter. Otherwise, the shell assembly  600  is constructed as described above. 
   In the foregoing specification, embodiments of the invention have been described with reference to numerous specific details that may vary from implementation to implementation. Thus, the sole and exclusive indicator of what is the invention, and is intended by the applicants to be the invention, is the set of claims that issue from this application, in the specific form in which such claims issue, including any subsequent correction. Any definitions expressly set forth herein for terms contained in such claims shall govern the meaning of such terms as used in the claims. Hence, no limitation, element, property, feature, advantage or attribute that is not expressly recited in a claim should limit the scope of such claim in any way. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense.