Abstract:
An example vehicle instrument panel includes a speaker for producing alert and warning sounds. A membrane prevents water from intruding into the speaker assembly and instrument panel. The membrane is spaced apart from the speaker and over an open end of the speaker housing. Sound energy from the speaker travels through an open space against the membrane. The membrane possesses acoustic properties to receive and pass on the sound energy.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     The application claims priority to U.S. Provisional Application No. 60/937,413 which was filed on Jun. 27, 2007. 
    
    
     BACKGROUND OF THE INVENTION 
     This disclosure generally relates to a speaker assembly mounted within a vehicle instrument panel for generating warning and alert tones. More particularly, this disclosure relates to a speaker assembly that is substantially resistant to water and that is installed on the face of a vehicle instrument panel. 
     Instrument panels in motor vehicles are required to be substantially water proof to prevent potential damage caused by any number of events that could result in liquid penetrating to the electrical devices and connections within the instrument panel. Because of the requirement to be waterproof, speakers are not included on an exposed face of the instrument panel, but are instead mounted deep within the instrument panel and under the dashboard. Such a location presents several disadvantages. In some instances the location of the speaker will mute or muffle the warning and alert noises such that the operator may not hear them. To overcome this problem, a larger and more powerful speaker may be required, at a corresponding increase in cost and space utilized. 
     Accordingly, it is desirable to develop a speaker for use within a vehicle instrument panel that can be mounted in a location favorable for directing alert sounds to a vehicle operator. 
     SUMMARY OF THE INVENTION 
     An example speaker for a vehicle instrument panel includes a membrane for preventing water from intruding into the speaker assembly and instrument panel. The membrane is spaced apart from the speaker and over an open end of a speaker housing. Sound energy from the speaker travels through an open space against a back side of the membrane. The membrane possesses acoustic properties to receive and pass on the sound energy. Because the example speaker assembly is water proof, it can be directed outward on the visible and exposed face of the instrument panel. Because nothing is obstructing sounds emanating form the speaker assembly, the sound quality can be improved along with increasing volumes to aid in alerting and warning a vehicle operator. 
     These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front view of an example instrument panel. 
         FIG. 2  is a schematic side view of an example speaker assembly. 
         FIG. 3  is an exploded view of the example speaker assembly. 
         FIG. 4  is a block diagram of the example speaker assembly. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to  FIG. 1 , a vehicle dashboard  11  includes an instrument panel  10  with speaker assemblies  12 . The speaker assemblies  12  emit sounds generated to alert a vehicle operator of specific vehicle conditions, such as for example a door open, keys left in the ignition or a warning when a fuel level goes low. The sounds generated are noises such as beeps, chimes or other tones familiar to a vehicle operator to warn and inform of current vehicle condition. The instrument panel  10  is required by vehicle manufacturers to be water proof. The example speaker assemblies  12  are pointed outward from the instrument panel  10  to improve the communication of sounds to an operator. 
     Referring to  FIGS. 2 and 3 , the example assembly  12  includes a speaker  22  mounted to a printed circuit board (PCP)  18 . The speaker  22  and circuit board  18  are mounted within a housing  16 . The example housing  16  is cylindrical and includes an open front end  48 . The open front end  48  faces outward from the instrument panel  10  similar to how a dial gauge is positioned and visible in the instrument panel  10 . Connectors  20  provide electrical communication between the PCP  18  and a circuit ( FIG. 4 ) powering the speaker  24 . The connectors  20  are as known in the art. 
     A membrane  24  extends over the open end  48  over the speaker  22 . The membrane  24  is spaced apart from the speaker  22  such that an open space is provided between the speaker  22  and the membrane  24 . The membrane  24  is held in place across the open end by a guide ring  26  and bezel  28 . The bezel  28  may provide for securing the membrane  24  in place along with the guide  26  or may simply provide a desired cosmetic appearance providing a desired look to the instrument panel  10 . 
     The membrane  24  is fabricated from a material that prevents water from penetrating through to the housing  16 . The specific material can be any material that provides a water resistant or water proof function. The membrane  24  also includes desired acoustic properties such that it is reactive to sound energy. The membrane  24  receives sound energy generated by the speaker  24  and communicates and amplifies that sound energy to project the desired sounds outward from the panel  10  toward an occupant of the vehicle. 
     The membrane  24  provides the function of preventing water from entering the speaker assembly  12 , while also performing the function of a speaker cone to further amplify and communicate sound energy from the instrument panel  10 . Sound energy generated by the speaker  22  is communicated to a back side of the membrane  24 . The membrane  24  vibrates in response to the sound energy from the speaker  24  and communicates that sound energy outward. The sound energy is amplified due to the larger area of the membrane as compared to the speaker  22 . 
     Referring to  FIG. 4 , the speaker assembly  22  includes an amplifier  30  powered by a power supply  34  and controlled by a microcontroller  32 . The power supply includes a positive lead  40  and a ground  42  that is connected to a vehicle power supply. A communication link  38  provides signal indicative of vehicle conditions to a communication hub  36  and further from the communication hub  36  to the microcontroller  32 . The microcontroller  32  actuates the amplifier to generate signals utilized by the speaker  30  to generate sound energy and specified frequencies and volumes to produce the desired tones. 
     The speaker  22  generates sound energy matched to the membrane  24  to produce the desired tone, chime or beep. The speaker  22  and membrane  24  act in concert within the housing  16  to produce the final audible tones. The housing  16 , speaker  22  and membrane  24  all factor into the end sound produced by the speaker assembly  12 . 
     Besides projecting sound energy from the speaker  22 , the membrane  24  protects and prevents water intrusion. This feature provides for the speaker assembly  12  to meet water proofing requirements of the instrument panel  10 . Because the example speaker assembly  12  is water proof, it can be directed outward on the visible and exposed face of the instrument panel. Additionally, it may be possible to utilize a smaller, less powerful speaker  22  as compared to prior art speakers that were required to be installed deep within the instrument panel and still provide an equal volume. Further, because nothing is obstructing sounds emanating form the speaker assembly, the sound quality can be improved along with increasing volumes to aid in alerting and warning a vehicle operator. 
     Although a preferred embodiment of this invention has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.