Abstract:
An acoustic door assembly generally comprises a door, a frame and a hinge. The door of the assembly is an insulated, acoustic door having a predetermined length. The frame of the assembly is positioned proximate the door and is joined thereto by the hinge. The hinge is a continuous, cam hinge having a length that is substantially equivalent to the predetermined length of the door and is secured along the length of the door.

Description:
FIELD OF THE INVENTION 
     The present invention relates to doors and, more particularly, to doors incorporating enhanced sound isolation features. 
     BACKGROUND OF THE INVENTION 
     Acoustic doors are a significant element in the realm of performing arts centers, concert halls, broadcast studios, auditoriums and movie theaters as well as in industrial applications where noise or voice privacy may be required. To effect noise or voice privacy, i.e. isolate and absorb sound, it is important that a door be insulated, however, it is also important that the door seal tightly and, if possible, completely against its supporting frame. 
     However, many designs focus only on the structure of the door itself ignoring the involvement of the frame in obtaining effective sound absorption. For instance U.S. Pat. No. 4,998,598 describes an acoustic door wherein the door is comprised of multiple panels, each panel having three layers, to of which are high density materials such as hardboard; a door supporting frame is not discussed. Likewise, U.S. Pat. No. 5,416,285 describes an acoustical door wherein the door is comprised of multiple plies the plies being separated by spacer networks; again, a door supporting frame and the additional sound absorption features it may provide in combination with the door is not discussed. 
     U.S. Pat. No. 5,371,987 does discuss an acoustic combination of a door and frame. Specifically, the &#39;987 patent describes an acoustical door and frame system wherein the door is secured to the frame via a plurality of cam hinges that are spaced along the length of the door. Upon closing the door against the frame, the cam hinges lower the door to be positioned against an elastomeric seal that extends along the sides and top of the frame. The elastomeric seals are held in adjustable retainers for positioning of the seals to create optimum interference with door and are compressed by the closing of the door. 
     The cam hinges used in the &#39;987 patent help to move the door into a desired sealing position against the frame, however, because the hinges are spaced periodically along the door, complete support is not provided to the door allowing for the possibility of warpage in the position of the door and, therefore, the possibility of reduced sound isolation. Further, the use of an elastomeric seal, i.e. a soft and possibly porous seal, allows for the possibility of gaps between the door and frame and, therefore again, the possibility of reduced sound isolation. 
     In view of the above, there is a need for an acoustic door assembly that addresses the acoustic benefits that can be provided by the combination of a door and its supporting frame. Further, there is a need for an acoustic door and frame combination that is able to provide complete support to the door, thereby preventing warpage and the possibility of reduced sound isolation, and that is able to provide a seal between the door and frame that is not subject to gapping. 
     SUMMARY OF THE INVENTION 
     The needs described above are in large measure met by an acoustic door assembly of the present invention. The acoustic door assembly generally comprises a door, a frame and a hinge. The door of the assembly is an insulated, acoustic door having a predetermined length. The frame of the assembly is positioned proximate the door and is joined thereto by the hinge. The hinge is a continuous hinge having a length that is substantially equivalent to the predetermined length of the door and is secured along the length of the door. 
     In a preferred embodiment, the hinge is a cam-lift hinge. Further, the insulated, acoustic door is preferably comprised of a first portion and a second portion where at least of a section of the first and second portion are separated by an insulating layer. The first portion is then crimped about the insulating layer to join the first portion of the door to the second portion of the door. The door also preferably includes a TEFLON® fabric-coated sweep and may or may not include a viewing window. The frame preferably includes a dual-magnetic seal to which the hinge is positioned externally. 
     A method of constructing an acoustic door assembly generally includes the steps of erecting a frame and securing an insulated, acoustic door to the frame through use of a continuous hinge. The continuous hinge has a length that is substantially equivalent to the length of the door and is secured to the door along that length. The hinge is preferaly a can-lift hinge. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of an acoustic door assembly of the present invention that includes a frame, door, and hinge; the door is in a semi-open position. 
     FIG. 2 is a cross-sectional view of the acoustic door assembly wherein the door is in a closed position. 
     FIG. 3 is a perspective of a first weldment of the frame of the acoustic door assembly. 
     FIG. 4 is a side view of the first weldment of FIG.  3 . 
     FIG. 5 is a top view of the first weldment of FIG.  3 . 
     FIG. 6 is a front view of a second weldment of the frame of the acoustic door assembly. 
     FIG. 7 is a cross-sectional view of the second weldment of FIG.  6 . 
     FIG. 8 is a top view of the second weldment of FIG.  6 . 
     FIG. 9 is a perspective view of a solid door and hinge of the acoustic door assembly. 
     FIG. 10 is a cross-sectional view of the door and hinge of FIG.  9 . 
     FIG. 11 is a perspective view of the door and hinge of the acoustic door assembly wherein the door incorporates a window. 
     FIG. 12 is a cross-sectional view of the door and hinge of FIG.  11 . 
     FIG. 13 is perspective view of a first portion of the hinge of the acoustic door assembly. 
     FIG. 14 is a side view of the first portion of the hinge of FIG. 13 prior to the winding of the hinge barrels. 
     FIG. 15 is a side view of the first portion of the hinge of FIG. 13 after the winding of the hinge joints. 
     FIG. 16 is a cross-sectional view of the first portion of the hinge of FIG.  13 . 
     FIG. 17 is a perspective view of the mating portion of the hinge of the acoustic door assembly. 
     FIG. 18 is a side view of the mating portion of the hinge of FIG. 17 prior to the winding of the hinge joints. 
     FIG. 19 is a side view of the female portion of the hinge of FIG. 17 after the winding of the hinge joints. 
     FIG. 20 is a cross-sectional view of the female portion of the hinge of FIG.  17 . 
     FIG. 21 provides a front and rear view of the acoustic door assembly of the present invention wherein the door incorporates a small window and is in the closed position. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     An acoustic door assembly  10  of the present invention, as depicted in FIGS. 1-21, and provides the user with improved sound isolation qualities. In general, acoustic door assembly  10  comprises a frame  12 , an acoustic door  14  and a hinge  16 . 
     Frame  12  is a split steel frame having a first weldment, i.e. first portion,  20  and a second weldment, i.e. second portion,  22 . First weldment  20  of frame  12  is depicted in detail in FIGS. 3-5. As shown, first weldment  20  includes a pair of side walls  24  and a top wall  26  that joins the tops of side walls  24 . Side walls  24  and top wall  26  incorporate a framing edge  28  that extends along the outer perimeter of each of walls  24  and  26 . A cross brace  30  extends between the lower inner comers of side walls  24 , and is included for shipping purposes only (removed upon installation of frame  12 ). One of side walls  24  incorporates a plurality of apertures  32  for insertion of rivet nuts  33  for the securing of hinge  16  to frame  12 . 
     Second weldment  22  of frame  12  is depicted in detail in FIGS. 6-8. As shown, second weldment  22  includes a first side wall  34 , a second side wall  36 , and a top wall  38  joining first side wall  34  and second side wall  36 . Each of walls  34 ,  36 , and  38  incorporates a framing edge  40  that extends along its outer perimeter. Further, top wall  38  includes a plurality of slots  39  that extend along its exterior; slots  39  are welding sites used to secure second weldment to first weldment  20 . Specifically, slots  39  are used to plug weld first weldment  20  to second weldment  22 ; additional welding to secure first weldment  20  and second weldment is provided  22  at the corners of the weldments  20 ,  22 . Screws  41 , shown by hidden lines in FIG. 2, secure side walls  34  and  36  to side walls  24  of first weldment  20 . 
     First side wall  34  incorporates a first seal support rail  42  and a second seal support rail  44 . First seal support rail  42  is bounded by a side wall  46 , a rear wall  48 , and a looped side wall  50 . Second seal support rail  44  is bounded by a side wall  52 , a rear wall  54 , and a looped side wall  56 . Via the various wall configurations, shown most clearly in FIG. 7, a substantially-square chamber  58  is formed intermediate first seal support rail  42  and second seal support rail  44 . 
     Second side wall  36  also incorporates a first seal support rail  60  and a second seal support rail  62 . First seal support rail  60  is bounded by a side wall  64 , a rear wall  66  and a looped side wall  68 . Second support rail  62  is bounded by a side wall  70 , a rear wall  72 , and a looped side wall  74 . Via the various wall configurations shown most clearly in FIG. 7, a rectangularly-shaped chamber  76  is formed intermediate first seal support rail  60  and second seal support rail  62 . 
     Referring to FIG. 2, additional detail regarding the sealing structure of frame  12  is provided. As shown, first seal support rail  42  and second seal support rail  44  of first side wall  34  are each provided with a unitary, extruded vinyl seal  79  that includes a clip portion  80  that is slid over support rails  42  and  44 . Each vinyl seal  79  further includes a central portion  82  that incorporates an air gap and an upper portion  84  that encases a magnet  85 . A substantially square foam absorber  86  is placed within chamber  58  and additional neoprene foam absorbers  88  are provided as indicated on FIG. 2. A layer of intumescent material  89  is provided proximate foam absorber  86 . 
     Likewise, first seal support rail  60  and second seal support rail  62  of second side wall  36  are each provided with a unitary, extruded vinyl seal  91  that includes clip portion  90  that is slid over support rails  60  and  62 . Each vinyl seal  91  further includes a central portion  92  that incorporates an air gap and an upper portion  94  that encases a magnet  95 . A rectangularly-shaped foam absorber  96  is placed within chamber  76  and additional foam absorbers  98  are provided as indicated on FIG. 2. A layer of intumescent material  99  is provided proximate foam absorber  96 . 
     With respect to foam absorbers  86  and  96 , they are comprised of open-cell urethane foam having two sides covered with non-woven cloth. Absorbers  86  and  96  are retained by interference-fit into chambers  58  and  76  and are captured by the geometry of the chamber. Pressure-sensitive adhesive may be applied to one or more of the surfaces of absorbers  86  and  96 , if desired, to prevent unauthorized removal of the absorbers. With respect to foam absorbers  88  and  98 , they are of a neoprene foam and are preferably adhered to frame  12 . Intumescent material layers  89  and  99  are provided to foam and expand when heated to prevent smoke and ignitable gases from getting past seals  79  and  91 , and are also adhered to frame  12 . 
     Referring to FIGS. 9 and 10, door  14  in a solid configuration is depicted. As shown, door includes a solid, outer leaf steel weldment  110  that is substantially planar in nature and a solid, inner leaf steel weldment  112  formed to include a pair of forward walls  114 , a pair of side walls  116  and a rear wall  118  joining side walls  116 . Outer leaf weldment  110  includes formed looping edges  120  that wrap about each of forward walls  114  crimping outer leaf weldment  110  to inner leaf weldment  112 . A layer of neoprene rubber insulation  122  is provided between looping edges  120  and forward walls  114 . Further, a recessed block of fiberglass insulation  124  is provided to the front and rear of inner leaf weldment  112 . The recessed blocks of fiberglass insulation  124  are separated by an insulating layer of air  126 . The lower portion of door  14  is provided with an adjustable height sweep  128  that is preferably coated in a TEFLON® fabric. Full length cam hinge  16 , described in further detail below, is shown in the open position and is secured to door  14  by welding. 
     Referring to FIGS. 11 and 12, door  14  incorporating a window  140  is depicted. Once again, door  14  includes an outer leaf weldment  142  and an inner leaf weldment  144  both incorporating an open window area  146 . Outer leaf weldment  142  is substantially planar in nature while inner leaf weldment  144  is formed to include a pair of forward walls  150 , a pair of side walls  152  and a rear wall  154  joining side walls  152 . Outer leaf weldment  142  is formed to include looping edges  156  that wrap about each of forward walls  150  thereby crimping outer leaf weldment  142  to inner leaf weldment  144 . A layer of neoprene rubber insulation  146  is provided between looping edges  156  and forward walls  150 . On either side of open window area  146  is provided an open-cell foam block  160  to provide sound absorption at the sides of open window area  146 . Blocks of fiberglass insulation  162  are provided, one to the front of inner leaf weldment  144  and one to the rear of inner leaf weldment  144 . The blocks of fiberglass insulation  162  are separated by an insulating layer of air  164 . The lower portion of door  14  is provided with an adjustable height sweep  166  that is preferably coated in a TEFLON® fabric. Full length cam hinge  16 , described in further detail below, is shown in the closed position and is secured to door  14  by welding. 
     With respect to window  140 , it is comprised of two panes of glass, one surface mounted to outer leaf weldment  142  and one to inner leaf weldment  144 . The edge of each pane of glass is surrounded by a u-channel rubber gasket  170 . A retaining strip  172  is placed over gasket  170  about the perimeter of window  140  and secured to door  14  with a plurality of button-head screws  174 . Each of screws  174  passes through outer leaf weldment  142  or inner leaf weldment  144  and threads into a pre-threaded weld nut  175  welded to the inner surface of the inner and outer leaf weldments  144 ,  142 , as shown in FIG.  12 . Window  140  may be of any suitable size and shape without departing from the spirit or scope of the invention, e.g. 20 inches by 64 inches as shown in FIGS. 1 and 11, 3 inches by 33 inches as shown in FIG. 21, etc. 
     Full-length cam hinge  16  is comprised of a first portion  180 , see FIGS. 13-16, and a mating portion  181 , see FIGS. 17-20, which extends the full length of door  14 . First portion  180  of cam hinge  16  is die-stamped to provide a plurality of barrels  182  and a barrel support  183 . Each of barrels  182  is provided with a first ramped end  184  and a second ramped end  186 , wherein second ramped end  186  additionally incorporates a notch  188 . Barrel support  183  is provided with a plurality of apertures  189  for the securing of cam hinge  16  to frame  12  with screws  190 , see FIG.  2 . After the die-stamping of first portion  180 , the plurality of barrels  182  are rounded, see FIG. 15, to produce the cross-section of FIG.  16 . 
     Mating portion  181  of full-length cam hinge  16 , FIGS. 17-20, is also die-stamped to provide a plurality of barrels  194  and a barrel support  195 . Each of barrels  194  is provided with a first-ramped end  196  and a second ramped end  198 , wherein second ramped end  198  incorporates a notch  200 . After the die-stamping of mating portion  181 , the plurality of barrels  194  are rounded, see FIG. 19, to produce the cross-section of FIG.  20 . Each of barrels  194  is positioned along barrel support  195  to mate with barrels  182  of first portion  180  such that first ramped end  184  mates with first ramped end  196  and second ramped end  186  mates with second ramped end  198 . A pin  202  secures first portion  180  to mating portion  182 . Rotation of mating portion  181 , which is fixed to door  14  by welding, relative to first portion  180 , which is fixed to frame  12  with screws, provides a lifting and a lowering, i.e. cam, action. 
     To assemble acoustic door assembly  10 , reference is made once again to FIG. 2 whereby it can be seen that first weldment  20  and second weldment  22  are joined to create frame  12  utilizing screws  41 , which are depicted with hidden lines. Additional insulating blocks  204 , of closed-cell urethane foam, are provided at the outer perimeters of frame  12  and are adhered to the inside of the frame. The user&#39;s door  14  of choice, e.g. with or without window  140 , is then secured to frame  12  by aligning apertures  189  of full-length cam hinge  16  with apertures  32  frame  12  and securing with screws  190  threaded into rivet nuts  33 . Referring to FIG. 1 (acoustic door assembly  10  in an open position) and FIG. 21 (acoustic door assembly  10  in a closed position, front and back), door  14  and frame  12  are preferably placed over a flat plate threshold  208  and are provided with a mortise style latch  209  and strike plate  210 . 
     In use, acoustic door assembly  10  provides the user with improved sound isolation qualities. Specifically, upon closing door  14  against frame  12 , see again FIG. 2, an uninterrupted dual magnetic seal  79 ,  91  is provided on each side of door  14  wherein each side of rear wall  118 ,  154  of inner leaf weldment  112 ,  144  is in contact with one of magnetic seals  79 ,  91  and each of looping edges  120 ,  156  of outer leaf weldment  110 ,  142  is in contact with one of magnetic seals  79 ,  91 . A magnetic seal is especially effective in enhancing sound isolation of door  14  as a complete seal, e.g. essentially no air gaps, exist between magnetic seals  79 ,  91  and metal door  14 . Air spring  82  helps to ensure a tight seal by compressing upon door  14  closing against frame  12 . Additional sound isolation is provided by the numerous foam portions, i.e.  86 ,  88 ,  96 ,  98 , and  204 , within frame  12  itself as well as the foam, air and fiberglass layers, i.e.  124 ,  160 , and  126  or  162 ,  160  and  164 , within door  14 . 
     Further sound isolation enhancement is provided by hinge  16 . The lifting, or cam, nature of hinge  16  ensures that door  14  is lowered into the appropriate position against frame  12  to ensure a substantially complete seal between frame  12  and door  14  as well as substantially complete sound isolation. The full-length nature of hinge  16  ensures complete support between door  14  and frame  12  thereby substantially eliminating any warpage between door  14  and frame  12 , and substantially eliminating the possibility of reduced sound isolation. 
     Because hinge  16  is outside of the magnetic sealing area, the seal created between magnetic seals  79  and door  14  is not disturbed by hinge attachment brackets and hardware. The adjustable height sweep that is preferably coated in a TEFLON® fabric,  128  or  166 , also helps to maintain sound isolation. Upon opening of door  14 , cam lift hinge  16  lifts door  14  so that the sweep seal  128 ,  166  lifts off the floor after a small amount of door swing. Thus, the sweep seal  128 ,  166  does not have to slide on the floor throughout the full travel of door  14 . As such, both sweep seal  128 ,  166  and the user&#39;s floor suffer minimal wear. In the instance of door  14  incorporating window  140 , sound absorptive features are also provided. Specifically, open-cell foam  160 , u-channel rubber gasket, and retaining strip  172  help to improve sound absorption. 
     Utilizing the above-described embodiment, acoustic door assembly  10  of the present invention, with or without a window, is able to provide the user with a desirable STC rating of 49. STC stands for “sound transmission class” and is a single number rating derived from measured values of sound transmission loss (TL) in accordance with the American Society for Testing and Materials (ASTM) E90 standards. TL through a door is a measure of its effectiveness in preventing the sound power incident on one side from being transmitted through it and radiated on the other side, taking into account the area of the door and the absorption in the receiving room. The STC provides a single number estimate of a door&#39;s performance for certain common sound reduction applications. A desirable fire rating of 45 minutes (door with 20 inch by 64 inch window) to one hour (solid door or door with 3 inch by 33 inch window) per UL  10 B is also provided by the present invention. 
     The present invention may be embodied in other specific forms without departing from the spirit of the essential attributes thereof; therefore, the illustrated embodiments should be considered in all respects as illustrative and not restrictive, reference being made to the appended claims rather than to the foregoing description to indicate the scope of the invention.