Abstract:
A locating device for locating the centerpoint of a body such as a recessed light fixture behind a ceiling. The device includes an extendable first member connectable in the center of the body and a second member positionable on the outer surface of the ceiling. A magnet positioned in the first member cooperates with a magnet positioned in the second member to maintain the second member in an aligned position with the center of the body. The extendable first member accommodates various size bodies so that the magnet positioned in the first member extends to the ceiling for attraction to the magnet positioned in the second member.

Description:
FIELD OF THE INVENTION 
   The invention relates to an apparatus and method for locating a device behind a wall or ceiling. 
   BACKGROUND OF THE INVENTION 
   During the construction of buildings and structures, object or bodies are fixedly associated or rigidly mounted with respect to structural frame members such as wood or metal studs. After the bodies are mounted to the structural frame members, sheet material such as drywall, paneling or plywood is placed over the structural members, concealing the bodies mounted to the structural members. Before the building or structure is complete, the sheet material must be cut or pierced to expose the bodies. Generally, the bodies are used for communicating electricity to or as light fixtures predetermined locations in the building. 
   SUMMARY OF THE INVENTION 
   The invention provides a locating device for finding a perimeter of a body allegedly positioned behind a sheet of material, such as a recess light mounted to a stud in position behind a sheet of drywall, paneling or ceiling material. In one aspect of the invention, the apparatus includes a first assembly having a magnet wherein the first assembly is securable to a center socket internal with respect to the body. The first assembly has adjustable means for adjusting the length of the first assembly with respect to the socket. The apparatus also includes a second assembly positionable on an outer surface of the sheet of material adjacent to the body. The second assembly has a magnet having an opposite polarity of the magnet of the first assembly. 
   In another aspect of the invention, the first assembly of the apparatus includes a stationary member having one end fixable to the socket and a movable member defining the adjustable means. The movable member is movable relative to the stationary member. 
   In yet another aspect of the invention, the stationary member is a tubular shaft member having an inner surface, having at least one depression formed therein. The movable member is a tubular shaft member having an exterior surface having at least one projection extending therefrom or receiving the at least one projection of the stationary member. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an exploded perspective view of the locating device according to the present invention; 
       FIG. 2  is a perspective view of the assembled locating device shown in  FIG. 1 ; 
       FIG. 3  is a perspective view of the locating device installed in a ceiling structure; 
       FIG. 4  is a perspective view of the locating device installed in the ceiling structure illustrating certain other feature; and 
       FIG. 5  is a schematic illustrating the drilling process to expose a recess fixture with the locating device. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring to  FIGS. 1 and 2 , the invention provides a located device  10  for locating a perimeter of a body  14  with respect to an outer surface of a sheet of material wherein the body  14  is rigidly positioned behind the sheeted material  16 . The locating device  10  includes a first assembly  18  positionable internal with respect to the body  14  and having a magnet  20  connected thereto. The locating device also includes a second assembly  22  positionable on an outer surface of the sheet of material  16  adjacent to the body  14 . The second assembly  22  includes a magnet  24  having an opposite plurality as the magnet  20  of the first member. The magnet  20  of the first assembly  18  cooperates with the magnet  24  of the second number  22 . 
   Referring now to  FIGS. 3 and 4 , the body  14  is rigidly positioned or immovably associated with a structural member  28 , such as a ceiling. The body  14  is positioned behind a sheet  16  of material. The sheet  16  defines a ceiling that can be formed from drywall, paneling, or ceiling squares. The locating device  10  of the present invention is advantageously used for locating recessed light fixtures  14 . The recessed light fixtures  14  are generally circular in having a center socket  30  for receiving a light bulb. The socket  30  defines the center of the peripheral edge  12  of the fixtures  14 . The socket  30  generally has interior threads (not shown) for threading a light bulb therein. 
   The first assembly  18  as shown in  FIGS. 1 and 2  include a first hollow shaft member  32  having a first end threaded  34  and sized for threading into the socket  30 . The first hollow shaft member  32  has a second opposing end  36  that is opened to a hollow interior  38 . The hollow interior  38  is sized and configured for receiving a tubular member  40 . The hollow interior  38  is splined  39  along a portion of its axial length. 
   The first assembly  18  also includes the tubular member  40  sized and configured for disposition within the hollow interior  38  of the first hollow shaft member  32 . The tubular member  40  has a splined exterior surface  42 . The tubular member  40  has an overall diameter slightly smaller than the inner diameter of the first hollow shaft member  32  so that the outer splined peripheral surface  42  of the tubular member  40  can be received within the splined hollow interior  38  of the first hollow shaft  32 ; and further so that the splined surface of the first hollow shaft member  32  meetingly mesh with the splined surface of the tubular member  40 . As a result, the tubular member  40  cannot rotate relative to the first hollow shaft member  32  when the first hollow shaft member  32  is fixed into the socket  30 . 
   The splined surfaces  39 ,  42  permit the two members  32  and  40  of the first assembly  18  to move axially or end wise in relation to each other. This configuration allows changes in the length of the first assembly  18  to accommodate various dimensions of recess light fixtures  14 . It is known that recess lighting features are available in difference sizes. The different sizes of the recess lighting fixtures affect the distance from the socket  30  to the ceiling member  16 . Therefore it is advantageous for a locating device to have a movable member  40  that will allow the first assembly  18  to lengthen so that the first magnet  20  is always positioned adjacent the ceiling material  16 . 
   The tubular member  40  has a first end  44  configured for maintaining the tubular member  40  within the axial length of the first hollow shaft member  32 . The tubular member  40  has an opposing second end  46  having an opening  48  for receiving the first magnet  20 . The magnet  20  may be connected to the tubular member  40  within the opening  48  by various conventional means including adhesive, clips, or threading the magnet  20  within the opening  48 . A housing  50  snaps onto the tubular member  40  and is secured over the magnet  20  in the end portion  48  of the tubular member  40 . The housing  50  has a center through aperture  52  so that the magnet  20  is exposed therefrom. 
   The second assembly  22  in the illustrated embodiment includes a two part housing for the second magnet  24 . The housing includes a short tubular member  54  and a disc-shaped member  60 . The short tubular member  54  has a central through opening  56  sized for receiving the magnet  24 . The through opening  56  is smaller at one end  58  to prevent the magnet  24  from falling therethrough. The opening  56  at end  58  allows the magnet  24  to sit essentially flush with the end  58  surface of the short tubular member  54 . Once the magnet  24  is installed within the short tubular member  54 , the disc-shaped member  60  has projections  61  that snap into apertures  62  formed along inner peripheral edge of the short tubular member  54 . The apertures  62  may be provided in small plates  64  secured and spaced along the inner peripheral edge of the short tubular member  54 . 
     FIG. 2  shows the locating device  10  in an extended position, wherein the tubular member  40  is at least partially exposed from the first hollow shaft member  32 . Although the second tubular member  40  extends from the second end  36  of the hollow interior  38 , the locating device  10  is assembled by installing the tubular member  40  into the hollow interior  38  of the first hollow shaft member  32  inserting the second end  46  of a second member  40  through the first end  34  of the first hollow shaft member  32 . The hollow interior  38  of the first hollow shaft member  32  has a splined portion  39  only extending a portion of its axial length starting at the second end  36 . The smooth portion  41  of the hollow interior  38  has a diameter essentially equal to the diameter of the splined portion  39  at the depression of the hollow interior  38 . As can be seen in  FIG. 1 , the first end  44  of the tubular member  40  is smooth and has a diameter that is slightly smaller than the smooth  41  diameter of the hollow interior  38  of the first hollow shaft member  32 . Therefore as the tubular member  40  is moved through the hollow interior  38  from the first end  34 , the smooth end  44  of the tubular member  40  is stopped by the projections forming the splines  39  in the hollow interior  38 . This limits the axial movement of the tubular member  40  relative to the first hollow shaft member  32 ; and further prevents the tubular member  40  from falling out of the first hollow shaft member  32  when the locating device  10  is secured to a socket  30 . Once the second end  46  of the tubular member  40  is exposed, the magnet  20  can be inserted into the hollow interior  38  at the second end  46  of the tubular member  40 . The cap/housing  50  is then secured to the second end  46  of the tubular member  40  and over the magnet  20  allowing the magnet  20  to be exposed through the aperture  52 . 
   As shown in  FIGS. 3 and 4 , a single assembly  18  can be secured to a socket  30  of the body  14 . The typical way for attaching the first assembly  18  to the socket is to threadably secure the first end  34  of the first hollow shaft member  32  to the threads provided in the socket. Other methods for attaching the first assembly  18  to the socket are via clips, clamps, a frictional plug etc. With the first assembly  18  in a vertical direction the tubular member  40  can slide out of the first hollow shaft member  32  via gravity to its fully extended length. When the sheet of material  16  for the ceiling is installed under the body  14 , the sheet of material  16  pushes a portion of the tubular member  40  back into the interior cavity  38  of the first hollow shaft member  32  so that the magnet  20  rests on the upper surface of the ceiling material  16 . 
   With the ceiling fully installed, the location of the first assembly  18  of the locating device  10  is hidden from view. The second assembly  22  is positionable on the outer surface of the sheet material  16  and adjacent the body  14  and magnet  20  of the first assembly. The magnets  20  and  24  cooperate in that one of the magnets exposed toward the ceiling sheet  16  has a “north” pole, or a positive plurality, and the other of the magnets exposed toward the ceiling sheet  16  has a “south” pole, or a negative plurality. The magnets  20 ,  24  cooperate such that the second assembly  22  is suspended on the ceiling sheet  16  by the magnetic attraction between the magnets  20 ,  24 . 
   Looking at  FIG. 5 , the center mark of the body  14  can then be used to find the perimeter of the body  14  for cutting or piercing the ceiling material  16  to expose the circular body  14  and socket  30 . The drill or piercing tool is placed adjacent the second assembly  22  and cuts outwardly from the center as shown by arrow “A”. When the drill or piercing tool contacts the inner perimeter of the body  14  the drill is then moved over to the outside perimeter of the body  14  and then continues drilling along the outside periphery  12  of the body  14 . The outside drilling procedure is shown by arrow “B”. The drill or piercing tool continues to follow the path around the outside perimeter of the body  14  until the entire area covering the body  14  interior is exposed. 
   The locating device  10  of the present invention has the advantages of providing a compact tool that is easily attachable to a socket  30  of a light fixture  14  and which accommodates various sizes of lighting fixtures  14  during a room or building construction. The locating device  10  provides an easy means for finding the peripheral edge  12  of the fixture  14  for properly cutting the ceiling material  16  to the exact dimension of the light fixture of the fixture  14 . Although the fixture  14  is shown having a circular peripheral edge, it is evident that the locating device  10  can be used on fixtures having rectangular, as well as other shapes. 
   While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiments but, on the contrary, is intended to cover various modifications and equivalent arrangements included with the spirit and scope of the appended claims, which scope is to be accorded the broadcast interpretation so as to encompass all such modifications and equivalent structures as is permitted under the law.