Abstract:
A smoke detector having a sound quality enhancement chamber for increasing the sound quality of alarms produced by a sound producing device in the smoke detector. In at least one embodiment, the sound quality enhancement chamber is formed by a housing and a plate such that the chamber is in communication with a sound producing device, which may be a speaker, for producing sounds, such as a human voice, with enhanced quality. The sound quality enhancement chamber acts as a spring and increases the quality of the sounds produced by the sound producing device of the smoke detector. In at least one embodiment, the sound quality enhancement chamber enables a smoke detector to emit a parent&#39;s voice that is clear and easily understandable.

Description:
FIELD OF THE INVENTION  
       [0001]     The invention is directed generally to smoke detectors, and more particularly, to smoke detectors capable of producing audible alarms.  
       BACKGROUND  
       [0002]     There exist numerous types of smoke detectors. Some smoke detectors produce an audible alarm, such as an alarm generated from a buzzer or a speaker, while other smoke detectors produce a visual alarm. The success of smoke detectors with audible alarms correlates directly with the quality of the sound generated by the smoke detector and the type of audible alarm produced. For instance, recent tests have shown that children experience deeper stages of non-rapid eye movement (NREM), particularly at stages three and four, than adults and have higher arousal thresholds. As a result, more often than not, children sleep through the alarms found in conventional smoke detectors. These tests have also shown that children are very likely to wake up from a deep sleep when they hear the voice of one of their parents.  
         [0003]     As a result of these tests, smoke detectors capable of replaying voice recordings have been developed that enable parents to record their voice on a smoke detector so that when the smoke detector detects the presence of smoke, the smoke detector plays the prerecorded voice of a parent instructing the child to wake up and leave the room as previously taught. Smoke detectors such as these have proved to be more successful in awakening sleeping children than conventional smoke alarms.  
         [0004]     While these recordable smoke detectors have been more successful in awakening sleeping children, these recordable detectors have not always performed adequately. For instance, the quality of a playback of a voice message is not always sufficient. More particularly, many smoke detectors suffer from having the inability to produce a loud, clear voice in a cost efficient manner. Thus, a need exists for a smoke detector having improved playback features for increasing the quality of voice playback in smoke detectors.  
       SUMMARY OF THE INVENTION  
       [0005]     The invention is directed to a smoke detector for detecting smoke and creating at least an audible alarm for informing occupants of a home of a fire. The smoke detector may include a detection device for detecting smoke, a sound producing device, which may be a speaker, for producing an alarm, a housing containing the speaker and the detection device, and a sound quality enhancement chamber forming a resonant element that is contained in the housing and is in communication with the speaker for increasing the quality of sounds produced by the speaker. The sound quality enhancement chamber may be formed from numerous sizes and materials.  
         [0006]     In at least one embodiment, the sound quality enhancement chamber may be formed from a plate and an inner surface of a housing forming a portion of the smoke detector. The plate may be attached to the inner surface, may form a gap between the inner surface of the housing and edges of the plate, or may be attached in other configurations. The speaker may be placed completely in the sound quality enhancement chamber or may be positioned in other configurations. Use of the sound quality enhancement chamber in the smoke detector enhances the quality of the sounds produced by the sound producing device. For instance, in at least one embodiment, addition of the sound quality enhancement chamber to a smoke detector has yielded an increase in output of a speaker from about 82 decibels for a smoke detector without a sound quality enhancement chamber to about 92 decibels for a smoke detector with a sound quality enhancement chamber with all other variables remaining constant. In addition, an increase of about two decibels from about 92 decibels to about 94 decibels has been realized when the plate forming a portion of the sound quality enhancement chamber is not attached to the housing and a gap exists between an inner surface in the housing and edges of the plate.  
         [0007]     Use of the sound quality enhancement chamber is particularly useful when the sound producing device emits a voice because the voice may be projected at higher decibels without increasing power consumption or altering other parameters of a smoke detector, which typically results in use of more expensive components. In addition, use of the sound quality enhancement chamber often times makes a voice produced by a speaker in a smoke detector clearer and easier to understand. These and other advantages and embodiments of the invention are described below. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]     The accompanying drawings, which are incorporated in and form a part of the specification, illustrate preferred embodiments of the presently disclosed invention(s) and, together with the description, disclose the principles of the invention(s). These several illustrative figures include the following:  
         [0009]      FIG. 1  is a perspective view of a smoke detector including aspects of this invention;  
         [0010]      FIG. 2  is an exploded view of  FIG. 1 ;  
         [0011]      FIG. 3  is a partial exploded view of  FIG. 1 ; and  
         [0012]      FIG. 4  is a bottom view of a portion of the smoke detector taken at lines  4 - 4  in  FIG. 3 . 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0013]     This invention is directed to a smoke detector  10 , as shown in  FIGS. 1-4 , usable to produce one or more alarms when smoke is detected by the smoke detector  10 . The smoke detector  10  includes a sound quality enhancement chamber  12 , as shown in  FIG. 3 , for increasing the quality of the alarm produced by the smoke detector  10  and for increasing other characteristics of the alarm sound. For purposes of this description, increased smoke alarm quality means broadening the frequency response of the sounds produced by the smoke detector  10  so that voices produced by the smoke detector  10  have proper tone.  
         [0014]     The sound quality enhancement chamber  12  enhances the sound produced by a sound producing device  14 , which may be, but is not limited to being, a speaker, a buzzer, or other appropriate device. Incorporation of the sound quality enhancement chamber  12  into the smoke detector  10  increases the sound producing capabilities of the smoke detector  10 . The sound quality enhancement chamber  12  may be included in a variety of smoke detectors for increasing the quality of the sound produced by the detector into which it is mounted and is not limited to being included only in smoke detectors similar to the detector described below.  
         [0015]     As shown in  FIGS. 2 and 3 , the smoke detector  10  may include a housing  16  adapted to be coupled to a base  18 . The housing  16  may be formed from any appropriate shape enabling the housing  16  to fit on the base  18 . The housing  16  may be formed from materials, such as but not limited to, plastics and metals. The base  18  may be attached to a wall, ceiling, or other structure in a building or, as shown in  FIG. 3 , may be releaseably attached to a bracket  20  that is configured to be attached to a wall, ceiling, or other structure. The base  18  may include a connection device  22  enabling the base  18  to be releaseably connected to the bracket  20 . The bracket  20  may include a plurality of holes enabling the bracket  20  to be screwed to a surface.  
         [0016]     The base  18  may also be configured to accept a control board  24 . The control board  24  may include a detection device  26  for detecting smoke, a microcontroller  28 , and other devices. The detection device  26  may be, but is not limited to being, an ionization detector, a photoelectric detector, or other appropriate detector. The microcontroller  28  may be programmable and capable of storing one or more alarm messages to be played when an alarm condition is recognized by the detection device  26 , or a test procedure is run, such as by a user depressing a button. The microprocessor  28 , the sound producing device  14 , and other electrical components may be powered by batteries contained in the smoke detector  10 , municipal power supplies, solar energy systems, or other power sources.  
         [0017]     In at least one embodiment of the invention, the microcontroller  28  may be capable of recording one or more alarm messages that are to be played by the sound producing device  14  when the detection device  26  detects smoke or undergoes a test run. The alarm message may be that of a parents voice instructing their child to wake up, exit the room in the manner they were taught, and meet outside at the family meeting place. For instance, the alarm message may include “Wake up Johnny, wake up. There is a fire in our house. Please exit your room as I taught you and meet me outside at our family meeting spot.” Such a message, when spoken by a parent, is very effective in awakening sleeping children as children are more prone to sleep through fire alarms and other sounds because they experience deeper non-random eye movement (NREM), such as at stages three and four, and children have a higher threshold for arousal than adults.  
         [0018]     The smoke detector  10  may also include the sound quality enhancement chamber  12  for increasing the quality of the sound produced by the sound producing device  14 . The sound quality enhancement chamber  12  may be formed from numerous materials and configurations. In at least one embodiment, the sound quality enhancement chamber  12  may be formed from the housing  16  and a plate  30 . While the plate  30  shown in  FIGS. 2 and 3  is shown as a relatively flat disc, the plate  30  is not limited to this configuration. Rather, the plate  30  may be any configuration for increasing the quality of the sound produced by the sound producing device  14 . In one embodiment, the plate  30  may be attached to an inner surface  32  of housing  16  to seal the plate  30  to the housing. The plate  30  may be attached to the inner surface  32  of the housing  16  using a caulk, a sealant, or other appropriate material, and if the plate  30  and housing  16  are made of metal, the plate  30  may be welded to the inner surface  32 . The inner surface  32  of the housing may have a substantially hemispherical shape or other appropriate shape forming the sound quality enhancement chamber  12 .  
         [0019]     In another embodiment, the plate  30  may not be in contact with the inner surface  32  of the housing  16 . Instead, one or more ports  33  may be in the plate  30  forming a vented sound quality enhancement chamber  12 . A vented sound quality enhancement chamber  12  has one or more apertures in the walls forming the chamber  12 . The ports  33  may take the form of one or more apertures in the plate  30  or may be a gap  34 , as shown in  FIG. 4 , present between edges of the plate  30  and the inner surface  32  of the housing  16 . The gap  34  may extend substantially around all edges of the plate  30 . In this embodiment, the plate may be attached to the base  18  using heat staking or other appropriate manners. The gap  34  may enable the plate  30  to vibrate and increase the quality of the sound emitted by the smoke detector. In at least one embodiment, the smoke detector  10  may include a plurality of gaps  34  between the plate  30  and an inner surface  32  of the housing  16  and a plurality of locations where the plate  30  is attached to the inner surface  32  of the housing  16 . The ports  33  may exist in the plate  30  or housing  16  and number one or more. In addition, the ports  33  may be of varying size and configuration. The ports  33  increase the quality of the sound emitted by the sound producing device  14 .  
         [0020]     The sound producing device  14  may be in communication with the sound quality enhancement chamber  12 , as shown in  FIG. 2 , such that sound waves produced by the sound producing device  14  are emitted into the sound quality enhancement chamber  12 . In at least one embodiment, the sound producing device  14  is positioned in the sound quality enhancement chamber  12 . The sound producing device  14  may also be mounted to the plate  30 . In yet another embodiment, the sound producing device  14  may be positioned in the sound quality enhancement chamber  12  proximate to the inner surface  32  of the housing  16 . In embodiments where the sound producing device  14  is a speaker and positioned proximate to the inner surface  32 , a front face of the speaker may be positioned proximate to the inner surface  32  of the housing  16 . The housing  16  may or may not include a grill  36  for emitting sound waves from the sound quality enhancement chamber  12 . In at least one embodiment, as shown in  FIG. 3 , the inner surface  32  of the housing  16  is substantially hemispherical except for a bulb  38  that forms a head for the grill  36 .  
         [0021]     The sound quality enhancement chamber  12  may be formed from different sizes and configurations. The sound quality enhancement chamber  12  may have a volume of between about seven cubic inches and about twenty cubic inches. In one exemplary embodiment of the smoke detector  10 , the sound quality enhancement chamber  12  may have a volume of about thirteen cubic inches. Numerous factors account for determining the proper size of the sound quality enhancement chamber  12 . For instance, the sound quality enhancement chamber  12  is a sealed volume of air that acts as a resonant element or a spring. This volume of air can be tuned to enhance the low frequency response of the sound producing device  14 . The size of the sound quality enhancement chamber  12  is determined by how low the frequency of the sound produced by the sound producing device  14  is desired to be and how loud the sound is desired to be. Thus, the size of the sound quality enhancement chamber  12  is dictated by the volume and frequency of the sound produced by the sound producing device  14 .  
         [0022]     In one exemplary embodiment, the sound quality enhancement chamber  12  has a volume of about thirteen cubic inches, and the smoke detector  10  includes an amplifier  40  for amplifying sound emitted by the sound emitting device  14 . The amplifier  40  can operate at about 3 volts at 250 milliamps, thereby enabling the amplifier to operate at about 90-95 decibels with an output about 0.75 Watts. The speaker is rated for one Watt average consumption and 1.5 Watts of peak power input. Inclusion of the sound quality enhancement chamber  12  with this setup enables sounds emitted from the smoke detector  10 , when tested about ten feet from the smoke detector  10 , to be about 10 decibels higher than smoke detectors  10  having this setup without the sound quality enhancement chamber  12 . This test was performed with a speaker pointing towards a sound meter, and the units are decibels in scale c, which are weighted for human hearing.  
         [0023]     In addition, smoke detectors  10  using a sound quality enhancement chamber  12  that is not attached to the inner surface  32  of the housing  16 , but rather is attached to the base  18  and includes gaps  34 , as shown in  FIG. 4 , between the plate  30  and an inner surface  32  of the housing  16 , realizes an even greater increase in decibels of sounds produced by the sound producing device  14 . For instance, in at least one embodiment, the use of gaps between the plate  30  and an inner surface  32  of a housing  16  enables sounds to be produced at levels of about 12 decibels louder than smoke detectors  10  without the sound quality enhancement chamber  12  and about 2 decibels louder than smoke detectors  10  with the sound quality enhancement chamber  12  and having the plate  30  attached and sealed to the inner surface  32  of the housing  16 .  
         [0024]     The foregoing is provided for purposes of illustrating, explaining, and describing embodiments of this invention. Modifications and adaptations to these embodiments will be apparent to those skilled in the art and may be made without departing from the scope or spirit of this invention.