Abstract:
An improved door hinge attachment device is provided. The device includes a plate formed separately of the door and door frame that is attached to a door or door frame. The device has elongate threaded bores alignable with screw holes in the hinge plates. The device is useful with metal doors and door frames. The attachment devices have projections on the backside thereof and may be provided with covers to prevent construction material or debris from fouling the threads in the threaded bores.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   This patent application claims priority to U.S. Provisional Patent Application Ser. No. 60/481,125 filed Jul. 23, 2003, the disclosure of which is incorporated herein by reference. 

   BACKGROUND OF INVENTION 
   Metal doors and metal door frames are well known in the art. A door is connected to the door frame by one or more hinges in a vertically spaced orientation. One common way to prepare a door or door frame for the installation of a hinge is to first form a metal attachment plate with a hinge plate recess. A recess in the plate has desired offset or depth to accommodate at least a portion of the thickness of the hinge plate. Screw holes are tapped in the attachment plate to form screw threads to accept screw fasteners. The attachment plate is then secured at a respective location to the door or door frame for receipt of a hinge plate in the recess and securement of a hinge to the door or door frame. Typically the attachment plates are thin and also are made of low strength steel such as cold rolled steel. Such an arrangement has offered a low pullout strength and often results in a thread failure or stripping of the tapped hole and failure of the door to operate properly and in some cases a failure of the door to open or close at all. Screw pullout strength can be a significant problem with heavy doors such as those used in prisons. Another current problem that exists during the installation of a metal door frame occurs when grout is poured into or other construction material is installed in the hollow area between the door frame and the building structure after the hinge attachment device is in place. A portion of the hinge attachment device is often exposed on the inside of the door frame. This permits any construction material, for example grout, put into the hollow space between the door frame and the building, to flow or move into contact with the hinge attachment device and enter the tapped screw holes making the screws hard or even impossible to install without removing the interfering construction material from the tapped holes. This may require retapping of the holes which often times will result in a threaded hole which is not useable because of the construction of the hinge attachment device. Such door and door frame constructions are of the type that are assembled at a work site without the hinge attachment screws already being in place. If the hinge attachment screws are in place during installation of the door frame, construction material may also adhere to and foul the screw threads. This would present a problem when the screws need to be extracted since the construction material would interfere with their extraction possibly causing damage to the screws or the threaded holes for the screws. 
   The present invention is directed to overcoming one or more of the problems set forth above. 
   SUMMARY OF INVENTION 
   The present invention relates to a hinge attachment device for use with metal doors and door frames providing ease of assembly and strong construction. 
   The present invention is generally directed to a hinged door construction and associated door hinges. The door and door frame are of a metal construction and the door may be of a hollow metal type. The door frame and door have hinge attachment devices secured thereto. Such attachment devices are made from a piece of metal that accommodates the width of the door and hinge attachment areas of the door frame and are preferably welded to the door and door frame. Projection weld spots may be provided on the hinge attachment devices. Threaded projections are provided on the hinge attachment device for securing the hinge plates to the outside of the door frame or outside of the door so that the hinge recesses in the attachment devices are planar accommodating a planar hinge plate. The threaded projections extend from the back of the attachment devices to significantly increase the pullout strength of the screws and hinge from the hinge attachment device. Protective cover or covering may be provided over the ends of the threaded projections when installed on the door frame to prevent foreign material from entering the threaded portion of the projections to prevent foreign material from fouling the threaded bores in the projections. By pre-locating and prethreading the hinge attachment device apertures and the projections, precise placement of the hinges on the door and the frame can be accomplished and thereby ensure correct alignment of the hinge plates when assembled with the door and door frame. 
   One aspect of the present invention is to provide a hinge attachment device that has threaded projections suitably attached thereto preferably of a high strength steel. The use of the hinge attachment device provides increased durability and ease of manufacturing. 
   Another aspect of the present invention is to provide projection weld spots on the attachment devices to improve securement of the attachment devices to either the door or door frame by welding. The use of protuberances or raised weld spots will allow for quick and accurate installation of the hinge attachment device and can be used to align the plate to cooperating and corresponding spots on the door or door frame. 
   Still another aspect of the present invention is to provide witness marks for security studs or electrical wiring on the exposed surface of the attachment devices if desired. This will facilitate drilling of holes for the installation of security studs or electrical wiring. The witness marks may be used for location and appropriate sizing of the holes needed. 
   Yet another aspect of this present invention is to provide means to protect the threaded projections to protect the screw threads in the projections from the entry of foreign material. The use of covers eliminates the need for costly processes like welding grout guards or hinge pockets to the frame. 
   These are merely some of the innumerable aspects of the present invention and should not be deemed an all-inclusive listing of the innumerable aspects associated with the present invention. These and other aspects will become apparent to those skilled in the art in light of the following disclosure and accompanying drawings. 

   
     BRIEF DESCRIPTION OF DRAWINGS 
     For a better understanding of the present invention, reference may be made to the accompanying drawings, where like numbers throughout the various Figures designate like or similar parts, in which: 
       FIG. 1  is a perspective view of a hinge attachment plate showing the surface that will be hidden when the plate is installed on a door or door frame; 
       FIG. 2  is a perspective view of the hinge plate of  FIG. 1  showing out the face that will be outside when installed on a door or door frame; 
       FIG. 3  is an exploded perspective view of a portion of a door and door frame with the door in an open position showing the hinge attachment devices and a hinge attaching the door to the door frame, hidden portions of the attachment devices are shown in phantom; 
       FIG. 4  is an enlarged perspective view of a preferred form of projection; 
       FIG. 5  is an enlarged fragmentary sectional view of the projection of  FIG. 4  attached to an attachment device; 
       FIG. 6  is an enlarged fragmentary sectional view of an alternative construction of projection and attachment device; and 
       FIG. 7  is an enlarged fragmentary sectional view of an additional alternative construction of projection and attachment device. 
   

   DETAILED DESCRIPTION 
   In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be understood by those skilled in the art that the present invention may be practiced without these specific details. In other instances, well-known methods, procedures and components have not been described in detail so as to obscure the present invention. For example, the invention can be applied to virtually any type of door utilizing a hinge. 
   A hinge attachment device, designated generally as  1 , is illustrated in  FIGS. 1 and 2 . The device  1  can be used for attachment to a door  2  and a door frame  3 , as shown in  FIG. 3 . The device is adapted to be used in both a door  2  and door frame  3  simplifying both production and inventory control. As shown, the device  1  includes a thin metal plate  8 , e.g. ⅛– 3/16″ thick, which has three generally planar portions  4 ,  5 , and  6  with the central portion  5  being positioned between and attached to the end portions  4  and  6 . The portions  4 ,  5 , and  6  are generally planar on their exposed or front major surfaces or faces  13 ,  24 ,  25 . A formed plate  8  also includes bights  7  that may be formed by suitably bending a generally planar sheet of metal cut to the correct dimensions and shape. The bights  7  connect the portion  5  at each end thereof to the respective portion  4  or  6 . The bight portions  7  may be inclined or generally perpendicular to the portions  4 ,  5 , and  6 . In some instances, the bights  7  may be continuous with portions  4 ,  5  and  6  making the hinge attachment device  1  effectively flat. Preferably, the attachment device is metal, such as low grade steel, e.g., cold rolled-type steel. 
   The plate  8  is provided with the plurality of suitably spaced and located apertures  11 , as shown in  FIG. 2 , passing therethrough between opposite exposed surfaces  12 ,  13  of the portion  5 . Projection members  14  are suitably secured to the back surface  12  of the portion  5  and project therefrom as seen in  FIGS. 1 ,  2 . One form of securement is by welding,  FIG. 6 , where the projection is denoted as  14 A. Alternatively, the projections  14  may be formed as integral parts of the plate  8 , as shown in  FIG. 7  where the projection is denoted as  14 C. The projections may also be secured to the portion  5  as by being press fit,  FIGS. 3 ,  5 , into formed holes in the plate  8  to ensure proper location and registration of the apertures  11  and the throughbores. Such press fit projections are denoted  14 B. The projections  14  each have an axially extending throughbore  17  that is suitably threaded. The projections  14  may be threaded before or after installation and with the apertures  11  and throughbores  17  suitably aligned, the apertures  11  may be threaded if desired by passing a tap or other threading device through a threaded bore  17  thus ensuring registration of the threads in the portion  5  and the projections  14 . 
   The projections  14  may be of any suitable cross-sectional shape such as hexagonal or cylindrical tubular members. The apertures  11  and throughbores  17  have longitudinal axes that are coaxial and which are generally perpendicular to the opposite surfaces  12 ,  13  of the portion  5 . The apertures  11  in the portion  5  may also have a countersink or the like at the exposed face  13  to ensure a hinge plate  21  of the hinge  23  will lie flat on the exposed face  13  in the event the respective screw holes  20  in the hinge plate may have a burr or the like which would prevent it from lying flat on the central portion  5 . 
   The plate  8  is bent at the bights  7  to create an offset of the exposed face  13  of the portion  5  from the faces  24 ,  25  of the portions  4 ,  6  respectively to provide a recess  26  for the hinge plate  21  to be positioned at the appropriate depth when mounted to the door  2  or door frame  3  to allow the edge  27  of the door to fit relatively tight with the face inside  28  of the door frame. The depth D, as shown in  FIG. 2 , of the recess  26  formed by the bights  7  and portion  5  will be determined by the thickness of the hinge plate  21  and the spacing needed between the edge face  27  of the door  2  and the inside face  28  of the door frame  3 . Preferably, the exposed face  29  of a hinge plate will be flush to below flush with the faces  27 ,  28  and/or the faces  24 ,  25  depending on construction of the attachment device  1  and the door  2  and/or door frame  3 . 
   Protuberances  31  and corresponding indentations  32  are provided in the portions  4 ,  6 . The protuberances  31  and indentations  32  are suitably located and present in suitable numbers to help effect securement of the device  1  to a respective door frame  3  or door  2 . The indentations  32  provide indications of the locations of where a welder should contact the device  1  in order to effect securement of the device  1  to the door  9  or door frame  10 . Securement can be accomplished by the use of a spot welder or the like, thus facilitating assembly of the devices  1  to either the door  2  or door frame  3 . 
   Suitable witness marks may be provided to indicate the location for holes that may be drilled before or after attachment of the devices  1  to provide for a security stud or wiring. As best seen in  FIG. 2 , there is a first set witness marks  33 ,  34 . The mark  33  indicates the outer perimeter of a hole to be drilled and the mark  34  indicates the center of the potential hole. The marks  33 ,  34  help align and size a suitable drill bit for drilling through the device  1  before or after attachment to a door  2  or door frame  3 . The hole  38 , as shown in  FIG. 3 , may be formed at the witness mark  33  and can be used to receive a security stud  37  on the hinge  23 . There is shown a second set of witness marks designated  35 ,  36  as best seen in  FIG. 2 . The marks  35  indicate the location of the outer perimeter of a hole to be drilled and the marks  36  indicate the center of the witness mark  35  for positioning of a drill bit or the like. The use of the witness marks  35 ,  36  help appropriately locate and size a hole to be formed for the installation of electrical wiring through the device and into the door  2  or door frame  3 . Also, the witness marks  35 ,  36  can be used to locate, for example, a switch device such as an electrical switch for use with a security system. Recesses may be formed at the marks  34 ,  36 , as by punching, to help center a drill bit for drilling a respective hole. Alternatively, through holes may be preformed at the location(s) of one or more of the witness marks  33 ,  35 . 
   Screws  40  are used to attach the hinge plates  21  and hence hinge  23  to the hinge attachment device  1  for the door  9  and the hinge attachment device  1  for the door frame  10  as desired. Hinge  23  includes a hinge pin  43  that pivotally connects the hinge plates  21  together. The hinge plates  21  have holes  20  that are sized and located to register with the apertures  11 . The projections  14  have a height H, as shown in  FIG. 1 , to provide a total threaded length in the portion  5  and projection  14  of preferably at least about one screw diameter. As shown, when installed, the hinge  23  mounts to the hinge attachment devices  1  and hence the door  2  and the door frame  3 . 
   One or more hinges  23  are used to mount the door  2  to the door frame  3  preferably after the door frame has been suitably installed in a doorway in a building structure. 
   As best seen in  FIGS. 1 and 3 , protective coverings  50  are attached to each of projections  14  to selectively seal the threaded bores  17 . The covering  50  may be molded plastic and sized to be retained on the projections by friction or interference fit. The covering  50  may also be vinyl, liquid plastic, self-adhesive covering, or other suitable material. The screws  40 , when installed may, if the threaded shanks  51  are longer than the depths of the threaded bores  14  and apertures  11 , simply move the covering  50  on the projections including moving a covering  50  off the projections  14 . 
   The method includes both the method of forming the attachment device  1  and the method of assembling a door to a door frame. The device  1  may be suitably formed from a generally planar sheet, of, e.g., metal, by bending it into the three portions  4 ,  5 ,  6  and forming the bights  7  therebetween as necessary. This can be done by stamping, rolling or extrusion. The device  1  may also be formed by extrusion. If extruded, an elongate strip of extrudate will be formed and cut transversely into the appropriate lengths. The projections  14  are suitably secured to the backside  12  of the plate  8  by any suitable method, as by welding, press fitting into apertures  11  on the backside  12 , etc.  FIGS. 4 and 5  illustrate a projection  14 B adapted for press fit attachment to the central portion  5 . The projection  14 B includes an enlarged head  61  and a coaxial shank  62  with a shoulder  63  therebetween. The shoulder  63  includes an axially projecting interference member  65  adapted to deform the center portion  5  when pressed thereinto to prevent relative rotation between the central portion  5  and projection  14 B. An outwardly projecting rib  67  may be provided to enhance the interference fit between the surface defining the aperture  11  and the shank  62 . The shank  62  is sized to also provide an interference fit of the shank with the center portion  5 . A preferred projection is a Strux nut from Textron. Preferably, the projection  14 B is made of a high-strength steel such as grade 8 steel which is preferably harder and stronger than the material forming the center portion  5 . Alternately, the plate  8  may be formed by die casting, see  FIG. 7 , or the like in which case the projections denoted  14 C may be integrally formed as part of the plate  8 . An aperture  11  and respective bore  17  may be formed with their axes being longitudinally aligned or coaxial. The bore  17  and apertures  11  may be threaded before assembly or after assembly as by tapping. Alternately, in the case of a die cast device  1 , the threading of the apertures  11  and bores  17  may be accomplished during the die casting process. The protuberances  31  and recesses  32  may be formed by punching or stamping. Alternately, if the plate  8  is die cast they may be formed during the die casting process. 
   The formed devices  1  may be attached to the door  2  and door frame  3  either at the work site or at the manufacturing plant. Preferably, the plates  8  are welded in place to the door  2  and door frame  3  wherein only the portion  5  is exposed. After attachment to a door  2  or door frame  3 , the plates  8  are inside the door except for the exposure of the portions  5 . 
   The hinge  23  is assembled to a respective door  2  or door frame  3  through the use of the screws  40 . If desired, holes may be formed at the witness marks  33 ,  35  and suitable equipment installed, as for example, electrical devices or the security stud  37 . The holes at the witness marks  33 ,  35  may be also pre-formed if desired. If the device  1  and the door frame  3  is to be subjected to possible exposure to a construction material or other material that could foul the threads in the threaded bores  17  or apertures  11 , coverings  50  may be installed over the projections  14  prior to the exposure of the problematic material to the device  1  and the door frame  3 . The screws  40 , if the length is sufficiently long, may simply push the covering  50  axially and longitudinally along the projection  14  until the screw  40  reaches the desired depth. Additionally, the screw  40  may push the covering  50  completely off the projection  14 . The covering  50  thus prevents fouling of the threads but does not interfere with the installation of the hinge  23  via the screws  40 . If the hinge  23  is separated into the two separate hinge plates  21  prior to attaching the plates  21  to the respective device  1 , the door may be lifted into place and the hinge pins  43  installed. Alternatively, the door  2  may be attached to the door frame  3  with the hinge plates  21  being attached to each other via the hinge pin  43 . 
   Although the preferred embodiment of the present invention and the method of using the same has been described in the foregoing specification with considerable details, it is to be understood that modifications may be made to the invention which do not exceed the scope of the appended claims and modified forms of the present invention done by others skilled in the art to which the invention pertains will be considered infringements of this invention when those modified forms fall within the claimed scope of this invention.