Sound insulator structure for window
United States Patent Okawa Apr. 8, 1975 SOUND INSULATOR STRUCTURE FOR 2.728.l 16 12/1955 Wesfilund 2 2.838.809 6/l958 Zeo WINDOW 3.553.9l3 l/l971 Eisenberg 52/172 nt Taro Okawa, -9,l-chome, Tokyo. 3,837,129 9 1974 Losell 52/6I6 Ja an p FOREIGN PATENTS OR APPLICATIONS [22] May 1.509.275 1/1969 Germany 52/6: [2|] Appl. No.: 473,295  
  Primary Exan1iner.lohn E. Murtagh 30 Foreign Appfication priority Dam Attorney. Agent, or FirmWenderoth, Lind &amp; Ponack Dec. 3, I973 Japan t. 48439784 [57] ABSTRACT [52] 52/172; g A sound insulator structure adapted to be set in a win- SI 1 t C 6 20 dow or door frame for insulating incoming sounds or 144 noises, comprising three sheets of glass arranged in a l l 0 care 52 parallel-spaced relation to each other and at least one I I of which has a different thickness from the two others, and a glass holding frame of elastic material provided [56] References cued with frame members for encircling and holding the UNITED STATES PATENTS edges of the three sheets of glass. l,9l3,2()5 6/1933 Lenhart 52/172 2525.717 10/1950 Ottcnheimer 52/172 6 Clam, 5 Drawmg Flgum PATENTED PR 8i975 (iii? 1 [1F 4 FIGJ LMENTEUAPR 81975 sum u 95 4} FIGS  1 SOUND INSULATOR STRUCTURE FOR WINDOW BACKGROUND OF THE INVENTION A conventional sound insulator structure in use for a window or door frame includes two sheets of glass ar ranged in a parallel-spaced relation to each other.  
  According to the known structure. however. the sound absorption or insulation is not satisfactory since when one sheet of glass receives sound waves from outside and is thereby caused to vibrate. the air in the space between the two sheets of glass is also caused to vibrate and influence the other sheet of glass in vibration. This could be avoided if there would be provided a greater spaced relation. that is more than 30 cm. be tween the two sheets of glass. However, it is not desirable or impossible because a window or door frame of commercial use is not thick enough to allow such structure to be set therein. If a window or door frame could be provided with such thickness, it would require an opening of a building for a window or door that is thick enough to allow such frame to be set therein. For this reason. the conventional structure has few uses of ap plications.  
  The present invention provides a sound insulator structure including three sheets of glass arranged in a parallel-spaced relation to each other and at least one of which has a different thickness from the others, and a glass holding frame of elastic material provided with frame members for encircling and holding the edges of the three sheets of glass. The sound insulator structure thus constructed is adapted to be set in a window or door frame.  
  As it is constructed such that a relatively smaller spaced relation is provided between the three sheets of glass. and the sheets of glass are caused to vibrate in different manners when sound waves strike against the outer or inner sheet of glass. it is possible to obtain a good sound absorption or insulation by absorbing sound repercussions that may follow vibrations of the sheets and window or door frames.  
 BRIEF SUMMARY OF THE INVENTION The sound insulator structure constructed according to the invention has uses for a door or window frame of metallic or wood material.  
  There are two different manners of mounting the structure in a window or door frame. One is the manner in which the glass holding frame is first set in a window or door frame with its frame members set in position and secured thereto by suitable means such as adhesive material. Three sheets of glass are then set in grooves of the frame members provided opposite the edges thereof. The other is the manner in which three sheets of glass are first set in the frame members, and the glass holding frame thus paned is then mounted in a window or door frame.  
  The sheets of glass are of different thickness, the outer and inner sheets being 3mm thick respectively. and the intermediate sheet being 5mm thick.  
  If any gaps are present between the frame members and the outer and inner sheets of glass held thereby or between the door or window frame and the frame members. the sound absorption or insulation will be adversely affected. In order to avoid this, surfaces of contact between the glass holding frame and the window or door frame should preferably be provided with curved surfaces so that the contacted surfaces may be securely joined together by pressure or by adhesive material. The frame members and the outer and inner sheets of glass held thereby should preferably be joined together by application of adhesive material. whereas the intermediate sheet of glass should preferably be set in the frame member freely. When sound waves strike against the outer or inner sheet of glass which is thereby caused to vibrate and influence the intermediate sheet of glass, the three sheets of glass are caused to vibrate in different manners or different numbers of vibration. This provides an effective means of absorbing or insulating noises that may follow vibrations of the glass sheets and door frame.  
  As the glass holding frame and its frame members are made of rubber material, it is possible to absorb vibrations occurring at the edges of the sheets, thus minimizing the amount of sound waves that may pass through the window or door frame.  
  Relatively small spaces such as 2.5cm. for example. may be provided between the three sheets of glass arranged in a parallel-spaced relation. so that substantially half the amount of incoming sounds or noises can be absorbed or insulated.  
 BRIEF SUMMARY OF THE DRAWING FIG. 1 is a front view of a preferred embodiment of the present invention.  
  FIG. 2 is an enlarged sectional view taken along the line A A in FIG. 1.  
  FIG. 3 is a sectional view, partly enlarged. of another preferred embodiment of the invention.  
  FIG. 4 is a sectional view, partly enlarged, of the embodiment set in a metallic door frame.  
  FIG. 5 is a diagram showing variations of the acoustic transmission loss with center frequencies of sounds.  
 DETAILED DESCRIPTION OF THE INVENTION As has been described in brief, the present invention provides a sound insulator structure adapted to be set in a window or door frame. comprising three sheets of glass arranged in a parallel-spaced relation to each other and at least one of which is of different thickness from the two others, and a glass holding frame of elastic material provided with frame members for encircling and holding the edges of the three sheets of glass.  
  By setting the structure in a door frame. for example, it is possible to minimize the amount of noises that may be produced by vibrations of the glass sheets and door frame when receiving incoming sound waves.  
  A good sound absorbing or insulating effect can thus be obtained regardless of types of material of the window or door frame used.  
  The present invention has uses for window or door frames of wood, wood base covered by metallic material or metallic material.  
  Now. the invention will be described by way of examples by reference to the accompanying drawings.  
  Referring first to FIGS. 1 and 2, a mm wide glass holding frame B of rubber material is provided with frame members, said frame members including grooves 4 and 5 provided opposite the edges of the sheets of glass 1 and 2 of 3mm thickness for encircling and holding said edges, and a groove 6 for a sheet of glass 3 of 5mm thickness. The grooves 4, 5 and 6 are provided in a parallel-spaced relation (about 2.5cm) to each other. Hollow portions 7 and 8 are provided between the grooves 4 and 6 and between the grooves 6 and 5, re spectively for receiving and supporting containers l0, [O for desiccant material 9.  
  When hollow portions 7 and 8 are provided in a rectangular shape. portions 7a and 8a are provided on the inner wall of the hollow portions 7 and 8 for supporting the containers 10, 10.  
  The surface areas 11 and 12 surrounding the spaces between the grooves 4, and 6 or sheets of glass 1, 2 and 3 set therein are covered with sound absorbing material such as felt layer or mohair sheet. or a great number of sound absorbing material of small length 13 planted thereon.  
  It is possible first to set the sheets of glass 1. 2 and 3 in the corresponding frame members or grooves 4, 5 and 6, so that the sheets are arranged in a parallelspaced relation to each other. The glass holding frame B thus paned is then mounted in a door frame 14 of wood material. In this case. the sheets of glass 1 and 2 are secured to the grooves 4 and 5 by application of adhesive material whereas the sheet of glass 3 is freely supported by the groove 6. Reference numeral 15 is an opening of a building for a door frame. 16 is a rotary shaft provided on a door frame of wood. 17 is a glass retainer. 18 is a protrusion provided on the inner wall of the door frame 14. and 51 is a packing.  
  According to the invention described above, the sheet of glass 1 is caused to vibrate upon receiving compression waves of sounds which strike against the sheet 1 from the arrow direction 19, followed by vibrations in the air in the space between the sheets 1 and 3. As the sheet 3 differs in thickness from the sheet 1 and is freely held by its corresponding groove 6, the sound waves are attenuated to a considerable degree upon impact on the sheet 3, going forward to the sheet 2 where the waves are echoed and further attenuated to pass through the sheet 2 in the arrow direction 20.  
  As illustrated above. the edge of the sheet 3 is not rig idly secured to or freely held by the groove 6 of the frame member, so that the sheet 3 produces vibrations in a differnt manner from the other sheets 1 and 2, and the vibrations are aborbed by its frame member. This provides an effective means ofincreasing the sound absorbing or insulating effect.  
  The spaces a and b between the sheets 1 and 3 and between the sheets 3 and 2 are connected to each other by means of gaps or clearances which are present at the edge of the sheet 3 held by its frame member.  
  The pressures in the spaces a and b may change with variations of the temperatures outside or in a room, but such changes can be automatically adjusted by the presence of the gaps or clearances to such an extent that the pressures which strike against both sides of the sheet 3 are kept to a constant level.  
  With wind pressures striking against the sheet 1, the pressure in the space a becomes higher and can resist the wind pressures. This increases the resistance of the sheet 1 against the pressure from outside.  
  A suitable number of holes 21 and 22 are provided to connect the spaces a and b to the hollow portions 7 and 8. respectively. The air in the spaces a and b is thus kept dry and at low humidity by the desiccant material 9 in the container 10.  
  In FIG. 3, a door frame C is shown which comprises a laminated wood material 23 ofa given thickness covered with aluminium material 24 and 25 thereon. The frame C is provided with grooves 26, 27 and 28 at the inner wall thereof arranged in a spaced relation and adapted to receive the sheets of glass 32, 33 and 34 having the edges thereof set in and held by the frame members 29, 30 and 31 of rubber material. In this case.  
 5 the frame members 29, 30 and 31 are provided separately.  
  The surface areas of the frame C surrounding the spaces 0 and d between the sheets 32 and 33 and between the sheets 33 and 34 are laid with fiber material 10 35 of small length. The outer and inner sheets of glass 32 and 34 are 3mm thick whereas the intermediate sheet of glass 33 is 5mm thick, for example. The sheets 32, 33 and 34 are arranged in a parallel-spaced relation (2.5cm) to each other.  
  FIG. 4 is a sound insulator structure embodying the invention, which is set in a metallic door frame. A glass holding frame 36 of rubber material is first mounted in an aluminium sash. The frame 36 comprises frame members provided with grooves 37, 38 and 39 for bolding the edges of the sheets 41, 42 and 43. The sheets of glass 41, 42 and 43 are then set in their respective frame members with the sheet 41 and 43 rigidly se cured thereto by adhesive means and with the sheet 42 freely held thereby. This is the same as described in FIG. 1. The surface areas of the frame 36 surrounding the spaces 0 and fbetween the sheets 41 and 42 and between the sheets 42 and 43 are provided with roughened surfaces 44. The sheets 41 and 43 are 3mm thick w whereas the sheet 42 is 5mm thick. but this is not limi tative. Reference numerals 45 and 46 are hollow portions provided at opposite sides of the frame 36 for housing a container 47 for desiccant material 48. Reference numerals 49 and 50 are holes provided to con- 35 nect the hollow portions 45 and 46 to the spaces 0 and There are two different manners of mounting the frame 36 in the aluminum sash as described earlier. One is the manner in which the frame 36 is first 40 mounted in the sash 40 and rigidly secured thereto by adhesive or like means. The sheets of glass 41, 42 and 43 are then set in the frame members of the frame 36. The other is the manner in which the sheets 41, 42 and 43 are first set in the frame members to form a block of the sheets arranged in a parallel spaced relation; the  
 frame 36 thus paned is then mounted in the sash 40.  
  The shapes in section of the aluminum sash and the glass holding frame may be varied without departing from the spirit of the invention, and are not limitative to the embodiments described heretofore provided that the glass holding frame is constructed such that its frame members hold the three sheets of glass securely in a parallel-spaced relation.  
  In FIG. 5, a diagram is given to shown variations of the acoustic transmission loss (dB) with center frequencies (Hz) of sounds for the following cases:  
  In the diagram, (1 is the case where three sheets of glass each of 5mm thickness are used, (2) is the case where the intermediate sheet of 5mm thickness and the outer and inner sheets each of 3mm thickness are used, and (3) is the case where the intermediate sheet of 8mm thickness and the outer and inner sheets each of 5mm thickness are used.  
  In all the cases. the three sheets of glass are spaced by 2.5cm parallel to each other, but this is not limitative. Namely, the spaces may be spaced by 3cm with the sound source side and by 2 cm with the other side.  
  It is clear from the diagram that the cases (2) and (3) have advantages over the case l in absorbing or insulating sounds of low frequencies (noises caused by vehicles, for example) and sounds of high frequencies (noises caused by airplanes. for example).  
 I claim:  
  1. A sound insulator structure adapted to be set in a window or door frame or the like, comprising three sheets of glass arranged in a parallel-spaced relation to each other and at least one of which or intermediate sheet of glass is of different thickness from the two other sheets of glass, and glass holding means of elastic material provided with a plurality of hollow portions on opposite sides thereof to house containers for desiccant material. frame members provided with grooves opposite the edges of said three sheets of glass and adapted to encircle and hold said edges, one of said frame members opposite said intermediate sheet of glass being adapted to hold said intermediate sheet of glass freely supported by said one of said frame members whereas the remainder of said frame members opposite said two other sheets of glass being adapted to hold said two other sheets of glass rigidly secured to said remainder by adhesive or like means. and means for absorbing incoming sounds provided on wall surfaces of said glass holding means surrounding spaces between said grooves or said three sheets of glass set therein.  
  2. A sound insulator structure as claimed in claim 1 adapted to be set in a sash of aluminium material.  
  3. A sound insulator structure as claimed in claim 1 adapted to be set in a window or door frame of wood material base covered with metallic material thereon.  
  4. A sound insulator structure as claimed in claim 1 wherein said means for absorbing incoming sounds comprises provision of roughened surfaces on said wall surfaces.  
  5. A sound insulator structure as claimed in claim I wherein said means for absorbing incoming sounds comprises provision of mohair-layered surfaces on said wall surfaces.  
  6. A sound insulator structure as claimed in claim 1 wherein said intermediate sheet of glass is of substantially greater thickness than said two other sheets of glass.