Patent Publication Number: US-6698156-B2

Title: Method and apparatus for hollow metal fabrication

Description:
BACKGROUND OF THE INVENTION 
     I. Field of the Invention 
     The present invention relates generally to the field of hollow metal fabrication, and more particularly to a method and apparatus for adding grout to hollow metal. 
     II. Description of the Related Art 
     Hollow metal manufacturing typically includes the construction of hollow metal components such as doors, door frames, window frames and the like. Hollow metal products are used commercially for sturdy structures such as office buildings. Commonly, hollow metal products are also used in the construction of prisons and other detention facilities where sturdy frames and doors are important for security. In addition to frames and doors, pre-fabricated prison cells are also constructed. 
     Typically, when a frame is built into a prison or detention facility structure, the hollow metal frame has a hole cut near the top of the frame and grout or cement is poured into the frame to provide further sturdiness to the structure. However, when the grout is added to the frame, the construction on the frame is typically not complete. Hinges, strikes, locks NAME OTHER COMPONENTS and other components have not yet been added to the frame. The frame typically includes screw holes and other apertures for receiving these components. 
     Grout guards are commonly added to the inside of the frame in order to maintain an airspace so that when the components are screwed onto the frame, there is no resistance from hardened grout. FIG. 1A illustrates a prior art grout guard  100  that is representative of the type of grout guard presently used. The grout guard  100  is affixed in the interior of a hollow metal door frame  105 . Typically a hinge reinforcement  110  is placed between the grout guard  100  and frame  105  in order to provide further support for the door hinge (not shown). Having the grout guard  100  affixed to the frame  105 , grout is prevented from entering the air space in which screws enter when the hinge is attached. FIG. 1B illustrates another example of a hollow metal frame  120  having a prior art grout guard  125 . The grout guard  125  is shown affixed to the frame  120 . An air space is maintained to prevent grout from entering the are in which a strike plate (not shown) is affixed to the frame  120 . 
     Often, the addition of these grout guards adds significant labor to the manufacture of hollow metal frames. The metal boxes also typically increase the material cost of the frame. 
     SUMMARY OF THE INVENTION 
     In accordance with the present invention and the contemplated problems which have and continue to exist in this field, the invention features a method and apparatus for maintaining the necessary air space for components in hollow metal frames while reducing the material cost of the frame and the labor associated with manufacturing the frame. 
     In general, in one aspect, the invention features an apparatus including substantially planar body having an upper surface and a lower surface, at least one grip connected to the upper surface and a plurality of air space retainers connected to and substantially perpendicular to the lower surface. 
     In an implementation, the apparatus also includes a substantially planar gasket having a first and second surface, wherein the first surface is in contact with the lower surface of the planar body, and wherein the air space retainers protrude from the second surface of the gasket. 
     In another implementation, the air space retainers is a substantially cylindrical rod having a first radius. 
     In another implementation, each cylindrical rod includes a gasket ring wrapped along the circumference of the rods, each ring having an outer radius larger than the first radius, wherein the ring is located at a point along the rod at a length measured from the lower surface of the body. 
     In another implementation, the cylindrical rod has a third radius located at a point along the rod where the rod intersects the body, wherein the third radius is greater than the first radius. 
     In another aspect, the invention features a grout guard including a substantially planar body having an upper surface and a lower surface at least one grip connected to the upper surface, a gasket connected to the lower surface and a plurality of cylindrical protrusions connected to and substantially perpendicular to the lower surface and to the gasket the protrusions each having a circular ring gasket around the circumference of the protrusions. 
     In yet another aspect, the invention features a grout guard kit including a hollow metal frame, a grout guard adapted to be attached and removed from the hollow metal frame and grout adapted to be added to the interior of the hollow metal frame. 
     In an implementation, the grout guard includes a substantially planar body having an upper surface and a lower surface, at least one grip connected to the upper surface, a gasket connected to the lower surface and a plurality of cylindrical protrusions connected to and substantially perpendicular to the lower surface and to the gasket. 
     In still another aspect, the invention features a method of manufacturing including forming a hollow metal frame, connecting one or more grout guards to one or more areas of the frame where components are to be added, adding grout to the interior of the frame and removing the grout guards after the grout hardens. 
     In an implementation, the grout guard is used only one time and disposed. 
     In another aspect, the invention features a method of installing a hollow metal frame including placing a hollow metal frame, attaching one or more grout guards to areas of the frame where components are to be added, adding grout to the interior of the frame, removing the grout guard when the grout hardens and adding the components to the frame. 
     One advantage of the apparatus is that the materials used in the manufacture of the apparatus and the material used to install the apparatus is less expensive than prior art grout guards. 
     Another advantage is that minimal necessary air spaces are maintained in the appropriate areas of hollow metal frames without the interference of larger bulkier grout guards. 
     Another advantage is that once the grout has hardened, the grout guard can be permanently removed from the frame and disposed. 
     Another advantage of the invention is that the air spaces created by the grout guard create a further aperture for screws to enter, providing further support for the threads of the screws. 
    
    
     Other objects, advantages and capabilities of the invention will become apparent from the following description taken in conjunction with the accompanying drawings showing the preferred embodiment of the invention. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1A illustrates a hollow metal frame having a prior art grout guard; 
     FIG. 1B illustrates a hollow metal frame having a prior art grout guard; 
     FIG. 2A illustrates a perspective view of an embodiment of a grout guard; 
     FIG. 2B illustrates a side view of an air space retainer; 
     FIG. 3 illustrates a grout guard having a gasket; 
     FIG. 4 illustrates a perspective view of a grout guard as it is inserted into a hinge mortise on a hollow metal frame; 
     FIG. 5A illustrates a side view of an embodiment of a grout guard inserted into a hollow metal frame; 
     FIG. 5B illustrates a side view of an embodiment of a grout guard inserted into a hollow metal frame filled with grout; 
     FIG. 5C illustrates a side view of a hollow metal frame filled with grout after an embodiment of a grout guard has been removed; 
     FIG. 6 illustrates a hollow metal door frame having a number of embodiments of a grout guard; 
     FIG. 7 illustrates a flow chart of an implementation of a hollow metal manufacturing process; and 
     FIGS. 8A-8D illustrate several alternative embodiments of grips for an embodiment of a grout guard. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to the drawings wherein like reference numerals designate corresponding parts throughout the several figures, reference is made first to FIG. 2A illustrates an embodiment of a grout guard  200 . The grout guard includes a substantially planar body  205  that is typically in the shape of a rectangle. Other geometric shapes of the body  205  can be chosen. The rectangular shape is chosen in this embodiment because is fits smoothly along the surface and edges of a door frame (not shown). 
     The grout guard  200  also includes a one or more grips  210  connected to one side of the body  205 . Typically the person who removes the grout guard  200  from the door frame can get a hold of the grout guard  200  by placing his fingers through the grips  210 . The user can then apply an outward force to remove the grout guard. In an implementation, the user places his ring middle and ring fingers through the grips  210  to remove the grout guard. It is understood that there are many other ways to remove the grout guard from the frame. In this embodiment, three grips  210  are chosen because the use of three fingers to remove the grout guard  200  has been determined to provide the best leverage for removing the grout guard  200 . 
     The grout guard also includes several air space retainers (screw hole plugs)  215 . The air space retainers are attached to the body  205  on the opposite side of the grips  210 , and protrude away from the body  205 . The air space retainers  215  fit into screw holes on a hollow metal frame and protrude into the frame to a distance that a screw typically protrudes when the screw is screwed into the frame. Therefore, when grout is poured into the hollow metal frame, the grout pours around the air space retainers  215 . When the grout hardens and the grout guard is removed, an air space is maintained at the location where the air space retainers  215  were located. The base  220  of the air space retainers  215  curves near the surface of the body  205 . FIG. 2B illustrates a side view of the body  205  and the air space retainer  215  showing the curved base  220 . The curved base  220  provides a sturdy base for the air space retainer  215 . It has been determined that when grout hardens around the air space retainers  215 , the retainers  215  tend to break close to the body  205 , when the grout guard  200  is removed from the frame and hardened grout. Although the curved base  220  prevents the air space retainers  215  from breaking, the grout guard  200  is typically a single use apparatus due to the possible destruction of the air space retainers  215  from multiple uses. 
     The grout guard  200  also includes a dead bolt hole air space retainer (dead bolt plug)  230 . The hinges for hollow metal door frames typically include a dead bolt hole that receive a dead bolt that is typically installed in metal doors. Therefore, the dead bolt hole air space retainer  230  maintains the air space needed in the hollow frame to receive a dead bolt after the  0 grout hardens. The dead bolt hole air space retainer  230  has a curved base  240  similar to the air space retainers  215 . 
     Referring still to FIGS. 2A and 2B, the grout guard  200  also includes a ring gasket  225 ,  235  on each of the air space retainers  215 ,  230  respectively. The ring gaskets  225 ,  235  are located around the circumference of the air space retainers  215 ,  230  at a distance away from the body  205 . The distance away from the body  205  is typically a distance that corresponds to openings on the a door frame (not shown). The ring gaskets provide a barrier from which grout can leak from the holes on the hollow metal frame. The ring gaskets  225 ,  235  are typically rubber or other durable but flexible material. The ring gaskets  225 ,  235  typically tear away from the air space retainers  215 ,  230  when the grout guard  200  is removed from the frame and hardened grout. The ring gaskets  225 ,  235  can either be removed or fall away from the frame. If the gaskets  225 ,  235  stay affixed to the grout, a screw can easily be inserted without interference from any remnants of the ring gaskets  225 ,  235 . The easy destructibility of the gaskets  225 ,  235  is one reason the grout guard  200  is typically a single use apparatus. 
     FIG. 3 illustrates a grout guard  300  having a gasket  325 . The gasket  325  includes several holes, such as dead bolt hole air space retainer hole  320 , that fit the air space retainers  310 , 315 . The gasket  325  typically fits flush against the surface of the grout guard planar body  305 . An adhesive can be added between the gasket  325  and the body  305  to provide a secure mechanical connection between the gasket  325  and the surface of the body  305 . The gasket  325  is typically a flexible material, such as neoprene. It is understood that other flexible and porous materials can be used for the gasket  325 . The gasket  325  is used to provide a deformable cushion between the body  305  of the grout guard  300  and a metal frame. This flexibility and deformability is necessary because of possible surface irregularities of the metal frame. The gasket therefore receives and cushions irregularities in the frame so that the body  305  of the grout guard  300  remains substantially straight or parallel with respect to the frame. A further description of the gasket  325  is discussed below with respect to the grout guard  300  operation. 
     FIG. 4 illustrates a perspective view of a grout guard  400  as it is inserted into a hinge mortise  405  on a hollow metal frame  410 . There are typically a number of hinge mortises such as mortise  405  on the door frame  410 . Each mortise  405  has a number of holes  415  into which screws are secured once a hinge (not shown) is placed on the mortise  405 . Each mortise  405  typically also includes a hole  420  into which a dead bolt (not shown) can be affixed. As described above, before hinges are affixed to the door frame  410  grout is typically added to the hollow frame  410 . Therefore, in order to reserve the air spaces for easy insertion of screws, the air space retainers  425  of the grout guard  400  are inserted into the holes  415 , 420 . Also, as indicated above, the body  430  of the grout guard is typically a rectangular shape so that it fits snugly into the mortise  405 . 
     FIG. 5A illustrates a side view of an embodiment of a grout guard  500  inserted into a metal frame  505  having a hollow interior  550 . The figure shows the grout guard  500  having grips  510 , a body  545  and air space retainers  520 ,  525 , and a gasket  540 . Each of the air space retainers  520 ,  525  respectively include ring gaskets  530 ,  535  at an approximate location interior the frame  505 , thereby providing a barrier preventing grout from leaking out of the frame  505 . The figure also illustrates a series of surface irregularities  545  along the surface of the frame  505 . The gasket  540  deforms accordingly at the locations of the irregularities  545  thereby maintaining a substantially uniform penetration of the air space retainers  520 ,  525  into the interior of the frame  505 . The irregularities  545  shown are exaggerated to show the operation of the gasket  540 . 
     FIG. 5B illustrates a side view of an embodiment of a grout guard  500  inserted into a hollow metal frame  505  filled with grout  555 . The elements of the grout guard  500  are the same as described with respect to FIG.  5 A. FIG. 5B can represent a side view of the frame  505  just as the grout  555  as it is freshly poured into the frame or at a time when the grout has hardened. 
     FIG. 5C illustrates a side view of a hollow metal frame  505  filled with grout  555  after an embodiment of a grout guard  500  has been removed from the frame  505 . As discussed above, the grout  555  is hardened prior to removal of the grout guard  500 . With the grout guard  500  removed, the mortise area  570  is shown. When the grout guard  500  is removed air spaces  560  have been retained because the air space retainers  520  diverted grout around the retainers  520 . Similarly an air space  565  has been retained by the retainer  525 . The gaskets  530 ,  535  (FIGS. 5A-5B) kept grout from pouring out of the screw holes and dead bolt hole. FIG. 5C illustrates the gaskets  530 ,  535  of FIGS. 5A-5B in a destroyed state. For example, a piece  571  of a gasket is shown still attached to an air space retainer  520 . Another piece  572  of a gasket is shown hanging out of an air space  560 . Another piece  573  of a gasket is shown on the air space retainer  525 . Another piece  574  of a gasket is shown stuck in an air space  560 . These examples of the broken gaskets are to illustrate the fact that the gaskets typically are destroyed when the grout guard  500  is removed from the grout  555  and frame  505 . In some instances, the gaskets may be in a condition similar to a condition when the grout guard  500  was first installed in the frame  505 . 
     FIG. 6 illustrates a hollow metal door frame  600  having a number of embodiments of a grout guard  605 . Each grout guard  605  is shown in place on the door frame in a respective mortise. The door frame  600  is standing alone and has not been placed in a wall. Door frames such as door frame  600  are typically shipped in this form. Grout can then be added when the frame  600  is delivered to its final destination. Since the grout guards  605  are not to be removed until the grout has been added and hardened, the guards  605  can be taped or otherwise attached to the frame  600  by tape/ribbon  610 . The tape/ribbon  610  can include warning text such as “DO NOT REMOVE UNTIL GROUT HAS HARDENED”. In this way, the final installers can be reminded not to remove the grout guards  605  until the grout has hardened and air spaces retained for hinge and other hardware attachments. 
     FIG. 7 illustrates a flow chart of an implementation of a hollow metal manufacturing process  700 . A hollow frame or any other hollow metal apparatus is manufactured  705 . The grout guards are attached  710  to the desired areas of the hollow metal frame. AS discussed above, these areas where the grout guards are attached are typically areas in which hardware such as hinges, strikes plates or other hardware are to be added and where it is necessary to retain air spaces in the hardened grout. Warning labels are affixed  715  over the grout guards to warn the installers that the grout guards are to remain in place while the grout hardens. The frames are typically shipped to their final destinations where the grout is then added  720  to the frame. The grout is allowed  725  to harden. Once the grout is hardened, the grout guards are removed  730  and the desired hardware is added  735 . The frame is then installed  740 . In another implementation, the frame can be installed, and then the grout added. There are several orders that can be followed for installation. The methods described above are not limited to any one order. FIG. 7 is illustrative of one order. 
     A number of embodiments have been described. Nevertheless, is will be understood that various modifications may be made without departing from the spirit and scope of the invention. Several examples are now illustrated. 
     FIGS. 8A-8D illustrate several alternative embodiments of grips for an embodiment of a grout guard. FIG. 8A illustrates an embodiment of a grout guard having a single large grip  800  that can typically be handled by the user&#39;s entire hand. 
     FIG. 8B illustrates an embodiment of a grout guard having two side handles  805  that can individually handled by the user&#39;s hands. 
     FIG. 8C illustrates an embodiment of a grout guard having two finger loops  810 , in contrast to the three loops that are described in the embodiments above. 
     FIG. 8D illustrates an embodiment of a grout guard having a single handle  815  that can be gripped by a user&#39;s hand. 
     The embodiments and methods described above have illustrated that grout is typically added to hollow frames. It is understood that the embodiments and methods described above can be used with other filling materials in hollow frames such as cement or other suitable material. 
     Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, various modifications may be made of the invention without departing from the scope thereof and it is desired, therefore, that only such limitations shall be placed thereon as are imposed by the prior art and which are set forth in the appended claims.