Abstract:
This invention provides an air seal system for loudspeakers where it is desirable to reproduce sound accurately and efficiently without loss in sound quality. The air seal system may include a housing, a baffle, and a cord gasket positioned in a gland to form an airtight seal between the baffle board and the housing. The gland may include a break. Secured in the break may be the cord gasket ends. The cord gasket ends also may be secured in a pocket, one or more notches, or in a retaining region.

Description:
BACKGROUND OF THE INVENTION 
     1. Technical Field 
     This invention relates to seals for loudspeakers, more particularly, to a system for securing the ends of a loudspeaker cord gasket. 
     2. Related Art 
     Typically, loudspeakers have a voice coil/diaphragm assembly attached to a baffle board. In turn, the baffle board and a housing are sealed together to form an enclosure containing a measure of air. The seal typically is sandwiched between the baffle board and the housing so that no air can escape from the sealed enclosure. 
     In operation, the voice coil moves the diaphragm back and forth to act on the air in front of the loudspeaker. The diaphragm compresses air in the enclosure when it moves in and rarefies (i.e., decompresses) air when it moves out. This creates pressure differences between the air inside the sealed enclosure and the air outside the sealed enclosure. The pressure differences act like a spring that keeps the diaphragm in the right position. As such, the diaphragm produces sound that is more precise when the seal is tighter. 
     An airtight seal between the baffle and the housing allows the diaphragm to covert the air in front of the speaker to audible sound efficiently. However, if the seal is not airtight, then the pressure differences will not be as great. As a result, the voice coil/diaphragm assembly may have to draw more power to reproduce audible sound accurately. Drawing more power increases the operating cost of the loudspeaker and/or leads to incompatibility with other audio components such as a power amplifier. Additionally, if the pressure differences are far from pressure differences in the loudspeaker design, some of the low-pitched sounds, such as the bass, may be lost. A listener may hear air leaks when playing music through a speaker that has a breach in the seal. Accordingly, there is a need for an airtight seal in a loudspeaker to reproduce sound accurately and efficiently without loss in sound quality. 
     Prior attempts to seal the baffle board and the housing have included the utilization of a flat foam gasket. However, the cutting process employed to manufacture the flat foam gasket undesirably created scrap pieces that resulted in waste and higher unit prices. These flat foam gaskets tore easily, were difficult to position due to their flexibility, and resulted in a large amount of inventory. 
     Another attempted solution involved the utilization of a liquid gasket material. Although the liquid gasket material did not result in scrap pieces, the liquid gaskets still resulted in handling problems and they were messy and inconsistent. Here, the utilization of a preprogrammed machine to apply the liquid gasket material seemed to overcome some of the handling problems. However, the initial machine cost for a robotic method was high and not practical for low volume, such as less than 100,000 unit, applications. Therefore, there is a need to provide a cost effective, airtight seal for a loudspeaker to reproduce sound accurately and efficiently without loss in sound quality. 
     SUMMARY 
     An air seal system positioned between a loudspeaker baffle and the housing is disclosed. The air seal system includes a cord gasket positioned in a gland of the baffle with the ends of the cord gasket passed through a break in the gland. The ends of the cord gasket may meet at the break and curve towards an interior of the baffle board without crossing one another. Alternatively, the ends of the cord gasket may meet at the break and overlap one another or may be secured in a pocket, one or more notches, or in a retaining region. 
     With the cord gasket ends secured through the break in the gland or in the pocket, a notch, or a retaining region, the baffle and the housing may be mated together minimizing the need for further handling of the flimsy cord gasket. This simplified process may decrease manufacturing time translating into a decrease in manufacturing costs. 
     Other systems, methods, features, and advantages of the invention will be or will become apparent to one with skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features and advantages be included within this description, be within the scope of the invention, and be protected by the accompanying claims. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       The components in the figures are not necessarily to scale, emphasis being placed instead upon illustrating the principles of the invention. In the figures, like reference numerals designate corresponding parts throughout the different views. 
         FIG. 1  is a perspective view illustrating an example implementation of an air seal system for a loudspeaker. 
         FIG. 2  is a detailed view of  FIG. 1  taken generally within enclosed line  2  of  FIG. 1 . 
         FIG. 3  is a perspective view illustrating a second example implementation of an air seal system for a loudspeaker. 
         FIG. 4  is an exploded view of  FIG. 3  taken generally within enclosed line  4  of  FIG. 3 . 
         FIG. 5  is a perspective view illustrating a third example implementation of an air seal system for a loudspeaker. 
         FIG. 6  is a perspective view illustrating a fourth example implementation of an air seal system for a loudspeaker. 
         FIG. 7  is a detailed view of  FIG. 6  taken generally within enclosed line  7  of  FIG. 6 . 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  is a perspective view illustrating a first air seal system for a loudspeaker. The loudspeaker  100  may include any components that support the conversion of electric signals into audible sound. Various embodiments of the loudspeaker  100  may include audio components such as a power amplifier and a voice coil attached to a diaphragm. 
     In one embodiment, the loudspeaker  100  may include an air seal system  102 . The air seal system  102  may include a baffle  104 , a housing  106 , and a cord gasket  108 . Assembling other components (not shown) with the air seal system  102  may form a sealed enclosure  110  containing an amount of air within an interior  112 . 
     The baffle  104  may be a member capable of supporting other components such as transducers, tweeters, horns, ports and other components of a loudspeaker. The housing  106  may be any structure forming an outer shell protecting the operational components of the loudspeaker. Positioned between the baffle  104  and the housing  106  may be the cord gasket  108 . 
     The cord gasket  108  may be fabricated of any material that contributes to forming a seal when compressed. The material may be a resilient rubber material, such as neoprene, nitrile, or butyl, and may include polytetrafluoroethylene. The cord gasket  108  may have a predetermined cross-section and length. The predetermined cross-section may include a circle, a diamond, a square, conic section or a combination or any or these cross-section shapes. In one embodiment, the cord gasket  108  may be cut from cord stock to a desired length. In another embodiment, an O-ring may be cut at one location to form the cord gasket  108 . 
       FIG. 2  is a detailed view of  FIG. 1  taken generally within enclosed line  2  of  FIG. 1 . As seen in  FIG. 2 , the cord gasket may be located in a gland  202 . The gland  202  may be a long, narrow channel that follows a path about a perimeter that is common to both the baffle board  104  and the housing  106 . 
     Processing of the cord gasket  108  may result in the cord gasket  108  defining a first end  204  and a second end  206 . As an example implementation to secure the first end  204  and the second end  206  of the cord gasket  108 , the air seal system  102  may utilize a male tongue  208  and a female groove  210 . Positioning the female groove  210  to cooperate with the male tongue  208  secures the first end  204  and the second end  206 . 
     The male tongue  208  and the female groove  210  may reside on different parts of the air seal system  102 . The male tongue  208  may reside on the baffle board  104  and the female groove  210  may reside on the housing  106 . In an alternate embodiment, the male tongue  208  may reside on the housing  106  and the female groove  210  may reside on the baffle board  104 . 
     In operation, the cord gasket  108  may be placed and/or pressed into the gland  202  of the housing  106  so that the first end  204  and the second end  206  overlap at a position that is adjacent to the female groove  210 . Placing the baffle board  104  against the housing  106 , the male tongue  208  may function to compress the overlapping cord gasket  108  into the female groove  210  on the housing  106 . 
     The air seal system  102  may provide an airtight seal such that sound may be reproduced while minimizing sound quality losses. However, the placement of the male tongue  208  and the female groove  210  on different parts of the air seal system  102  may sometimes cause difficulties during the loudspeaker assembly process of mating the baffle  104  to the housing  106 . For example, dimension tolerances during manufacturing may vary such that the positional relationship between the male tongue  208  and the female groove  210  may be less than ideal. Additionally, an overlap distance (by which the first end  204  and the second end  206  overlap one another) may vary from unit to unit. As a result, these variations may increase the assembly time of aligning the overlapping ends  204 ,  206  between the male tongue  208  and the female groove  210 . An increase in assembly time results in undesirable increase in overhead costs for the loudspeaker  100 . 
     As such,  FIG. 3 ,  FIG. 5 , and  FIG. 6  show three embodiments utilizing various embodiments of cord gasket end securing mechanisms. Placing the cord gasket end securing features on one part of an air seal system functions to decrease the time it takes to assemble a speaker housing and a baffle board together. A skilled person in the art may utilize one or more of these features in any embodiment without departing from the spirit of the invention. 
       FIG. 3  is a perspective view illustrating a second example implementation of an air seal system  300  for a loudspeaker  302 ,  FIG. 1 . The air seal system  300  may include a cord gasket  304 , a baffle board  306 , and a housing (not shown). The cord gasket  304  may include a segment  308  disposed between a first end  310  and a second end  312 . The baffle board  306  may define a perimeter  314  having an interior  316 . 
       FIG. 4  is an exploded view of  FIG. 3  taken generally within enclosed line  4  of  FIG. 3 . In this embodiment, the first end  310  and the second end  312  meet and curve towards the interior  316 ,  FIG. 3 , of the baffle board  306  without crossing one another. The first end  310  may include a bend  402 ,  FIG. 4 , and a limb  404 . The bend  402  may represent a change in direction of the cord gasket  304  between the segment  308  and the limb  404 . The bend  402  may follow a curved path, an angled path, a sharp path, or any combination of these paths. 
     The limb  404  may extend from the bend  402  to a tip  406 , where the tip  406  resides at a furthest most location along the cord gasket  304 . In one embodiment, the limb  404  may include a head  408 . The head  408  may represent a change in direction of the limb  404 . 
     The second end  312  of the cord gasket  304  may have one or more features that are similar to the features of the first end  310 . For example, the second end may include a bend  410  and a limb  412 . The limb  412  may extend from the bend  410  to a tip  414 , where the tip  414  may reside at a furthest most location along the cord gasket  304  from the tip  406 . In one embodiment, the limb  412  may include a tail  416 . The tail  416  may represent a change in direction of the limb  412 . 
     To secure the ends  310 ,  312  of the cord gasket  304 , the baffle board  306  may include a gland  418  and a passage  420 . The gland  418  may extend around the perimeter  314 ,  FIG. 3 , of the baffle board  306  to provide an interference fit for the cord gasket  304 . The passage  420 ,  FIG. 4 , may represent a break in an interior wall  422  of the gland  418  and may be configured to receive the cord gasket  304  such that the first end  310  and the second end  312  may be compressed into one another to provide a localized airtight seal. 
     The passage  420  may define any profile, including a rectangular profile, curved profile or a trapezoid profile. If the interior corners of the passage  420  are curved, the passage  420  may define a U-shape profile. Preferably, the width of the passage  420  may be less than two times the cross-sectional diameter of the cord gasket  304 . The height of the passage  420  may be less than, equal to, or greater than the height of the gland  418 . 
     Extra material at the ends  310 ,  312  of the cord gasket  306  may provide some flexibility when assembling the cord gasket  304  into the gland  418 . To account for this extra material, the passage  420  may include a pocket  424  and/or a notch  426 . The pocket  424  may define a cavity into which at least one of the head  408  and the tail  416  may be placed. The depth of the pocket  424  may be greater than the depth of the gland  418  to account for varying lengths of cord gasket. In one embodiment, the depth of the pocket  424  may be approximately 0.5 inch to 1.0 inch in depth. Alternatively, at least one of the limb  404  and the limb  412  may extend to and/or be press fit into the notch  426 . In this example, the width of the notch  426  may be less than the combined cross-sectional diameter of the first end  310  and the second end  312 . 
     As seen in  FIG. 4 , a first rib  428  and a second rib  430  may form the pocket  424 . Under certain circumstances, the thickness of the baffle board may prevent the first rib  428  and the second rib  430  from forming a pocket. For example, sink marks are depressions that prevent the finish surface of an injection-molded part from being flat. Sink marks typically occur in a plastic injection molding process on the opposite side of a rib or other thick structure. As such, the thickness of the baffle board may at times prevent the utilization of ribs in the forming a pocket. 
     In response,  FIG. 5  is a perspective view illustrating a third example implementation of an air seal system  500  for a loudspeaker (not shown). Similar to the embodiment of  FIG. 3 , the first end  310  and the second end  312  seen in  FIG. 5  meet and curve towards the interior of a baffle board without crossing one another. However, the air seal system  500  may be employed in baffle boards that have thickness that might otherwise result in sink marks. 
     The air seal system may include the cord gasket  304  and a baffle board  502 . The baffle board  502  may include a gland  504 , a first wall  506 , and a second wall  508 . The first wall  506  and the second wall  508  may form a passage  510 . The passage  510  may represent a break (i.e., opening) in an interior wall  512  of the gland  504 . Placing and/or pressing the ends  310 ,  312  of the cord gasket  304  into the passage  510  of  FIG. 5  may secure the ends  310 ,  312 . 
     To further secure the ends  310 ,  312  of the cord gasket  304 , the first wall  506  may include a tab  514  and the second wall  508  may include a tab  516 . The tab  514  may extend as a protrusion from the first wall  506  towards the tab  516  to define a gap  518  and a retaining region  520 . A distance of the gap  518  may be less than a cross-sectional diameter of the cord gasket  304  to prevent either end  310 ,  312  from falling outside of the retaining region  520 . In an alternate embodiment, the tab  516  may be eliminated and the tab  514  may extend towards the second wall  508  to form the gap  518  with the second wall  508 . 
     To provide quick insertion of the cord gasket  304  through the gap  518 , the tab  514  and the tab  516  each may be chamfered (i.e., beveled or grooved) to define a V-shaped groove  522 . The V-shaped groove  522  may define an angle that may range from approximately 25 degrees to 150 degrees. Additionally, the tab  514  and the tab  516  may flex when pressed from a first side and configured to remain rigid when pressed from a side facing the retaining region  520 . 
       FIG. 6  is a perspective view illustrating a fourth example implementation of an air seal system  600  for a loudspeaker (not shown). Unlike the embodiments of  FIG. 3  and  FIG. 5 , the first end  310  and the second end  312  may cross one another after meeting in the air seal system  600 . As seen in  FIG. 6 , the first end  310  and the second end  312  may cross one another at an angle that is less than 180 degrees and extend towards an interior  601  of a baffle board  602 . The air seal system  600  performs well even when the air pressure inside a speaker enclosure is low. 
     The air seal system  600  may include the cord gasket  304  and the baffle board  602 . The baffle board  602  may include a passage  604  formed in an interior wall  605  of a gland  606 . The passage  604  may include features that permit compressing an overlapping portion of the cord gasket  304  to substantially the same compression percentage as the segment  308 . 
     As shown in  FIG. 6 , the baffle board  602  may further includes a first wall  608  having a first notch  610  and a second wall  612  having a second notch  614 . The wall  608  and the wall  610  may meet to form a pocket  616 . The first end  310  of the cord gasket  304  may be secured in the second notch  614 . Moreover, the second end  312  of the cord gasket  304  may be secured in the first notch  610  at a location remote from the first end  310 . 
       FIG. 7  is a detailed view of  FIG. 6  taken generally within enclosed line  7  of  FIG. 6 . In this embodiment, a depth  702  of the passage  604  may be large enough to permit compression of an overlapping portion  704  of the cord gasket  304  to substantially the same compression percentage as the segment  308 . For example, if the cross-sectional diameter of the cord gasket  304  is 0.125 inches and it is desired to compress the cord gasket  304  by 25%, then a depth  706  of the gland  418  may be 3/32 inches and the depth  702  of the passage  504  may extend 3/32 inches to ¼ inches beyond the depth of the gland  418 . 
     While various embodiments of the invention have been described, it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible within the scope of this invention. Accordingly, the invention is not to be restricted except in light of the attached claims and their equivalents.