Patent Publication Number: US-7724912-B2

Title: Speaker assembly

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The invention relates to a speaker assembly. More particularly, the invention relates to a speaker assembly with reduced size and weight, yet retaining robust structural integrity and simplified integration allowing optimum placement and excellent performance of the speaker assembly within an aircraft. 
   2. Description of the Prior Art 
   The current global community has made it possible for people from around the country, and around the world, to interact for both business and personal reasons. For many people, this requires they spend considerable time traveling from one location to another location. More often then not, these people travel in aircraft. 
   Whether these people travel in private or commercial aircraft, they desire high quality entertainment during the many hours they spend within the confines of an aircraft. While, high quality entertainment, for example, digital video with CD quality sound, is readily available for theatre and home use, the weight and size requirements for use of such equipment in an aircraft makes it very difficult to incorporate high fidelity systems within an aircraft. This problem is especially pronounced for audio speaker assemblies when one attempts to meet the size, weight and shape requirements for use in aircraft. 
   The aircraft industry places great priority upon component weight and size reduction. Range and payload are adversely affected by conventional terrestrial designs. These concerns are notable when one attempts to make changes within smaller private jets. For example, a small increase in the weight carried by an aircraft results in a substantial increase in the fuel consumption of the aircraft. In addition, the limited space available within an aircraft dictates the use of any space within the aircraft be carefully considered by those responsible for ensuring the comfort of passengers. 
   Lightweight and compact audio speakers are currently available. These speakers, however, substantially compromise sound quality for reduction in size and weight. With this in mind, an individual wishing to add an audio system to an aircraft must make a choice between high fidelity speakers, which do not suit the size and weight requirements of the aircraft or lower quality speakers providing desirable size and weight characteristics. 
   Another concern encountered in the incorporation of speakers within an aircraft is the fact the speakers are generally confined within an enclosed space offering little in the way of airflow for cooling the driving components of the loudspeakers. In addition, the small spaces available within an aircraft also dictate that the speaker housing be relatively small. This further creates heating problems as little air is available within the housing for the cooling of speaker components. As such, speakers are susceptible to overheating, which may result in damage thereto or failure of the component. 
   More particularly, and as those skilled in the art will certainly appreciate, the voice coil of a conventional driver generates heat which is then dissipated to the surrounding driver structure, that is, the driver magnet, etc. This heat must be “bled off” to maintain the driver at an appropriate operating temperature or the performance of the speaker will be compromised. 
   A need, therefore, exists for a speaker assembly providing high-fidelity sound, while also accommodating the size and weight constraints of an aircraft. The present invention provides such a speaker assembly. 
   SUMMARY OF THE INVENTION 
   It is, therefore, an object of the present invention to provide a speaker assembly including a rigid, structurally stable and self supporting housing within which at least a first driver is mounted and enclosed. The housing includes a first aperture formed in a first wall of the housing. The first driver includes a cone coupled to a driver magnet for generating sound. The driver magnet is seated within the first aperture exposing a portion of the driver magnet to an exterior of the housing. The driver magnet is encircled by a resilient gasket member, the gasket member being shaped and dimensioned to permit airflow about the magnet. 
   It is also an object of the present invention to provide a speaker assembly wherein the gasket member is positioned between an inner surface of the first wall of the housing and the first driver. 
   It is also another object of the present invention to provide a speaker assembly wherein the gasket member includes a series of open spaces between the gasket member and the driver magnet such that as the first driver is actuated, moving air within the enclosure of the housing, the air is forced through the open spaces such that it circulates about the magnet in a manner cooling the driver magnet. 
   It is also a further object of the present invention to provide a speaker assembly wherein the open spaces extend about the driver magnet. 
   It is another object of the present invention to provide a speaker assembly wherein the open spaces are created by forming the gasket member with a step construction. 
   It is still another object of the present invention to provide a speaker assembly wherein the gasket member includes an annular base secured directly to the inner surface of the first wall, and a series of spaced first elevation members secured to the base defining open spaces therebetween. 
   It is a further object of the present invention to provide a speaker assembly including a series of spaced second elevation members secured to the respective first elevation members in a manner further defining open spaces. 
   It is yet a further object of the present invention to provide a speaker assembly including a second driver mounted and enclosed within the housing. The housing further includes a second aperture formed in the first wall of the housing. The second driver includes a cone coupled to a driver magnet for generating sound. The driver magnet is seated within the second aperture exposing a portion of the driver magnet to the exterior of the housing. The driver magnet is surrounded by a resilient gasket member, the gasket member being shaped and dimensioned to permit airflow about the magnet. 
   It is also an object of the present invention to provide a speaker assembly wherein the gasket member is non-flammable closed-cell foam. 
   It is also a further object of the present invention to provide a speaker assembly wherein the gasket member is positioned between an inner surface of the first wall of the housing and the first driver and the first driver is compression fit between the gasket member and a second wall such that a top edge of the first driver contacts an inner surface of the gasket member and a bottom edge of the first driver contacts the second wall with a compressive force being applied to the first driver by the gasket member and the second wall between which the first driver is positioned. As such, the first driver becomes part of the internal bracing of the housing adding to the structural stability of the loudspeaker assembly. 
   It is another object of the present invention to provide a speaker assembly wherein the first driver is a mid range driver. 
   Other objects and advantages of the present invention will become apparent from the following detailed description when viewed in conjunction with the accompanying drawings, which set forth certain embodiments of the invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of the speaker of the present invention with the grill removed. 
       FIG. 2  is a partial cross sectional view of the speaker of the present invention. 
       FIG. 3  is a top plan view of the speaker housing of the present invention with the grill removed. 
       FIG. 4  is a top plan view of the grill. 
       FIG. 5  is a side plan view of the speaker housing with the drivers removed. 
       FIG. 6  is a side plan view of the speaker housing perpendicular to that shown in  FIG. 5 . 
       FIG. 7  is a perspective view of the speaker housing with the grill and drivers removed showing the foam gasket members in accordance with a preferred embodiment. 
       FIG. 8  is a cross sectional view of the housing shown in  FIG. 7  along the line VIII-VIII. 
       FIG. 9  is a perspective view of the speaker housing with the grill and drivers removed showing the foam gasket member in accordance with an alternate embodiment of a preferred embodiment. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The detailed embodiments of the present invention are disclosed herein. It should be understood, however, that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. Therefore, the details disclosed herein are not to be interpreted as limiting, but merely as the basis for the claims and as a basis for teaching one skilled in the art how to make and/or use the invention. 
   With reference to  FIGS. 1 to 8 , a speaker assembly  10  is disclosed. The speaker assembly  10  incorporates a variety of features which reduce the size and weight of the speaker assembly  10  without compromising the integrity of the sound generated by the speaker assembly  10 . The speaker assembly  10  also incorporates various features which improve the cooling thereof and ultimate performance of the speaker assembly  10 . 
   The speaker assembly  10  is primarily intended for use in aircraft, where weight and size are critical. While the speaker assembly is preferably designed for use in aircraft, the speaker assembly may be used in a variety of environments, such as wall and closed room speakers, automotive speakers or within personal computers, without departing from the spirit of the present invention. 
   As those skilled in the art will appreciate, the present speaker assembly has been disclosed without the wiring commonly employed in conjunction with speakers. As such, a variety of conventional wiring techniques may be employed within the spirit of the present invention. 
   Briefly, the speaker assembly  10  includes a rigid, structurally stable and self supporting speaker housing  12  within which at least a first driver  28  is mounted and enclosed. The speaker housing  12  includes a first driver aperture  40  formed in a first wall (or closed top wall)  14  of the speaker housing  12 . The first driver  28  includes a cone  36  coupled to a driver magnet  42  for generating sound, wherein the driver magnet  42  is seated within the first driver aperture  40  exposing a portion of the driver magnet  42  to the exterior  41  of the speaker housing  12 . 
   The driver magnet  42  is surrounded by, and supported upon, a resilient, closed cell foam gasket member  46 . As will be discussed below in greater detail, the foam gasket member  46  is shaped and dimensioned to permit airflow between the foam gasket member  46  and the driver magnetic  42 , and, therefore, about the driver magnet  42 . The flow of air in this way permits cooling of the driver magnet  42  via the passage of cooler air over the driver magnet in a manner which results in the evacuation of the heat developed by the electrical and physical interaction of the voicecoil (not shown) and driver magnet  42 . The foam gasket member  46  also permits movement of the first driver  28  relative to the closed top wall  14 . However, and as will be appreciated based upon the following disclosure, the path between the foam gasket member  46  and the driver magnetic  42  is substantially tortuous thereby limiting the passage of sound waves therebetween. 
   More particularly, the speaker assembly  10  includes a speaker housing  12  with a base structure  13  composed of a closed top wall  14 , closed first and second lateral side walls  16 ,  18  and closed front and rear side walls  20 ,  22 . The stability of the speaker housing  12  is further enhanced through the utilization of full penetration welds in the connection of the various walls thereof. The closed top wall  14  forms a support surface upon which first and second mid range drivers  28 ,  30  are mounted. Other than the driver apertures  40 , the closed top wall  14 , closed first and second lateral side walls  16 ,  18  and closed front and rear side walls  20 ,  22  are solid and impervious to the passage of sound waves or airflow. 
   The speaker housing  12  further includes a grill  32  which is selectively secured to the side walls  16 , 18 ,  20 ,  22  to maintain the mid range drivers  28 ,  30  therein as described below in greater detail. The speaker housing  12  is preferably constructed from aluminum, although other materials may be employed without departing from the spirit of the present invention. The grill  32  is constructed with grill ports  33  shaped and dimensioned for alignment with the cones  36  of the drivers  28 ,  30 . Other than the grill ports  33 , however, the grill  32  is solid and impervious to the passage of sound waves or airflow. In this way, the speaker housing  12  is a substantially closed enclosure with only the grill ports  33  permitting the passage of sound emitted by the drivers  28 ,  30  and the foam gasket members  46  permitting the passage of air between the foam gasket member  46  and the driver magnet  42  (and ultimately out of the enclosure defined by the speaker housing  12 ). 
   In accordance with a preferred embodiment of the present invention, the closed top wall  14  is substantially rectangular, although other shapes may be employed without departing from the spirit of the present invention. Four corner mounts  24  respectively extend from their respective ends of the front and rear side walls  20 ,  22 . Each corner mount  24  includes an aperture  26  adapted for attaching the speaker assembly  10  within the fuselage of an aircraft. The corner mounts  24  attach to a mounting bracket (not shown) of the aircraft. The mounting bracket is adapted to facilitate the installation of the present speaker assembly  10  within an aircraft fuselage. 
   The active components of the speaker assembly  10  include first and second mid range drivers  28 ,  30 . As explained in commonly owned U.S. Pat. Nos. 6,463,160 and 6,719,090, which are incorporated herein by reference, the mid range drivers  28 ,  30  are compression fit within the speaker assembly  10 . In particular, they are held between the closed top wall  14 , in particular, the gasket member  46  which sits upon the closed top wall  14 , and the grill  32  of the speaker assembly  10 . 
   In practice, and with reference to the first mid range driver  28 , the grill  32  is bolted to the base structure  13 , in particular, the grill  32  is secured to the exposed edges of the first and second lateral side walls  16 ,  18  and the front and rear side walls  20 ,  22  with screws. In this way, the base structure  13  and the grill  32  form an enclosure within which the mid range driver  28  is held. Although the first mid range driver  28  is disclosed herein in detail, those skilled in the art will appreciate the following description applies equally well to the second mid range driver  30 . 
   The mid range driver  28  is positioned within the enclosure defined by the grill  32  and the base structure  13  such that the interior surface  34  of the cone  36  is directed toward the grill  32 . In fact, the upper edge  38  of the cone  36  has a radius which is in alignment with an outer edge of the grill port  33  formed in the grill  32 . 
   The mid range driver  28  is compression fit between the closed top wall  14  of the speaker housing  12  and the grill  32  such that the interior surface  34  of the cone  36  of the mid range driver  28  faces the grill  32 . The exterior upper edge  38  of the cone  36  is directly attached to the grill  32  along the grill port  33  to provide a port for the transmission of sound. Secure attachment is achieved by using screws or adhesive (or other coupling structures) to securely attach the mid range driver to the grill  32 . 
   The compression fit of the mid range driver  28  within the enclosure defined by the grill  32  and the base structure  13  is further enhanced by forming a driver aperture  40  within the top closed wall  14 . The driver aperture  40  is shaped and dimensioned to receive and support the magnet  42  and the mid range driver  28 . The driver magnet  42  of the mid range driver  28  is seated within the driver aperture  40 . Specifically, the closed top wall  14  is formed in such a way to provide a space in which the back plate  44  of the driver magnet  42  may fit while the remainder of the driver magnet  42  sits on the gasket member  46 , which in turn sits on the inner surface  43  portion of the closed top wall  14 , adjacent the driver aperture  40 . As such, a portion of the driver magnet  42  of the mid range driver  28  is encircled by a resilient, non-flammable foam gasket member  46  and is fit within the driver aperture  40  to essentially become part of the closed top wall  14 . In this way, the foam gasket member  46  is positioned between the inner surface  43  of the closed top wall  14  and the mid range driver  28 . 
   By positioning the gasket member  46  between the mid range driver  28  and the inner surface  43  of the closed top wall  14 , the resilience of the gasket member  46  permits incursion and excursion of the mid range driver  28  during operation thereof. As will be discussed below in greater detail, this movement enhances performance of the present speaker assembly  10  by enhancing cooling and absorbing undesirable resonance. 
   In accordance with a preferred embodiment, the foam gasket member is composed of ENSOLITE IV1, a closed cell foam material made from a blend of a Poly Vinyl Chloride (PVC) and Nitrile Butadiene Rubber (NBR). Although a preferred material construction is contemplated for the gasket member in accordance with a preferred embodiment of the present invention, it is contemplated the gasket member may be formed from a variety of resilient materials adapted for permitting the compression fit and the flow of air about the magnet. 
   In addition to allowing for the compression fit of the driver magnet  42  within the driver aperture  40 , the foam gasket member  46  also prevents rattling of components within the speaker assembly  10 . The foam gasket member  46  is also positioned such that leads  66  of the driver  28  sit within the foam gasket member  46  in a manner preventing resonance thereof. 
   The foam gasket member  46  also permits movement of the mid range driver  28  during incursion and excursion of the cone  36 . By supporting the mid range driver  28  in a manner which permits movement of the mid range driver  28  relative to the closed top wall  14 , improved performance is achieved by minimizing undesirable mid range resonance commonly encountered when drivers are positioned within a small enclosure. The foam gasket member  46  further functions to absorb undesirable mid range frequencies as a result of the closed cell construction thereof. 
   Airflow about the magnet  42  is achieved by forming a series of open spaces  47  between the foam gasket member  46  and the driver magnet  42 , wherein the open spaces  47  extend about the driver magnet  42 . The open spaces  47  provide a tortuous path from the interior  68  of the enclosure defined by housing  12 , to the space between the inner surface  62  of the foam gasket member  46  and the outer surface  60  of the driver magnet  42 , and to the exterior  41  of the housing  12 . In this way, as the mid range driver  28  is actuated, moving air within the enclosure of the speaker housing  12 , the air is forced through the open spaces  47  in the foam gasket member  46 , and between the outer surface  60  of the driver magnet  42  and the inner surface  62  of the foam gasket member  46 , such that it circulates about the magnet  42  in a manner cooling the driver magnet  42 . 
   In addition to providing for the cooling of the driver magnet  42  as air passes thereby, the ability of compressed air to escape the enclosure as the open spaces  47  permit during movement of the driver  28 ,  30  reduces interferences between the first and second mid range drivers  28 ,  30  as vibrations generated by the drivers  28 ,  30  are either absorbed by the foam gasket members  46  or escape the enclosure via the opens spaces  47 . The ability of the present structure to reduce interference between drivers supported within the same enclosure, could be extended to speaker arrays by permitting the mounting of multiple drivers within the same enclosure without worrying that various drivers will interfere with each other. 
   More particularly, because of the nature of midrange-resonance propagation in small enclosures there are inherent benefits in mitigating the midrange resonances utilizing the closed-cell foam gasket member  46  under compression damping both the “box” (that is, the housing) and the driver frame. Additionally, as the drivers  28 ,  30  move air into and out of the enclosure defined by the speaker housing  12  in a manner proportionate to the amplitude of the audio signal being reproduced, it becomes possible to incorporate multiple drivers  28 ,  30  within the enclosure without creating a compounding effect normally associated with multiple drivers in the same enclosure. The “compounding effect” is a result of the change of air pressure on the unexposed or “backside” of the driver cone which is significantly increased by the presence of one or more additional drivers within the same airspace. Certain frequencies are exaggerated by this effect, always to the detriment of accurate sound reproduction. While it is possible to reduce this effect electrically, doing so adds weight, cost and complexity to the system and does not provide the critical benefit of using the air movement to cool the voicecoil/magnet structure. 
   In accordance with a preferred embodiment, the open spaces  47  are created by forming the foam gasket member  46  with a step construction. That is, the foam gasket member  46  includes an annular base  48  which is secured directly to the closed top wall  14 . Extending from the base  48  are four first elevation members  50  secured to the exposed upper surface  52  of the base  48 . Extending from the first elevation members  50  are respective second elevation members  54 . The base  48 , first elevation members  50  and second elevations members  54  define three levels along the upper surface of the foam gasket member  46 . The three levels are in the form of steps, the first level being the exposed upper surface  52  of the base  48 , the second level being the upper surface  56  of the first elevation members  50  (which is covered by the second elevation members  52 ) and the third level being the exposed upper surface  58  of the second elevation members  52 . 
   Although a preferred foam gasket member construction is disclosed above in accordance with a preferred embodiment of the present invention, the spacing may be created in various other ways. For example, and with reference to  FIG. 9 , the foam gasket member may be constructed such that the foam gasket member  146  includes an annular base  148  which is secured directly to the closed top wall  14 . Extending from the base  148  are four first elevation members  150  secured to the exposed upper surface  152  of the base  148 . Extending from the first elevation members  150  are respective second elevation members  154 . The base  148 , first elevation members  150  and second elevations members  154  define three levels along the upper surface of the foam gasket member  146 . The three levels are in the form of steps, the first level being the exposed upper surface  152  of the base  148 , the second level being the exposed upper surface  156  of the first elevation members  150  and the third level being the exposed upper surface  158  of the second elevation members  152 . 
   In addition to providing a secure enclosure for the mid range driver  28 , positioning of the driver magnet  42  within the closed top wall  14  of the housing  12  provides space saving in the profile of the speaker assembly  10 . This provides critical additional space for reducing the profile of the present speaker assembly  10 . Positioning of the driver magnet  42  within the driver aperture  40  also helps to align the mid range driver  28  within the speaker housing  12 . 
   In addition to reducing the profile and weight of the speaker assembly  10 , the present design improves the structural integrity of the speaker assembly  10 . By compression fitting the mid range driver  28  between the driver aperture  40  of the closed top wall  14  and the grill  32 , the mid range driver  28  becomes part of the internal bracing of the speaker assembly  10  and add to the structural stability thereof. The exposed magnet  42  also provides a natural heat sink for cooling the mid range driver  28 . 
   It is also contemplated one may wish to include a public address driver  70  within the speaker assembly. As such, the grill  32  may be formed with a public address port  72  about which the cone  74  of the public address driver is secured in a conventional manner. 
   As discussed above, although the disclosed embodiment shows a speaker assembly with only first and second mid range drivers, it is contemplated the speaker assembly may include various drivers, including tweeters and public address drivers, without departing from the spirit of the present invention. 
   While the preferred embodiments have been shown and described, it will be understood that there is no intent to limit the invention by such disclosure, but rather, is intended to cover all modifications and alternate constructions falling within the spirit and scope of the invention.