Abstract:
A combined heat sink and mounting bracket for a powered loudspeaker of a ported reflex type is provided. The combined heat sink and mounting bracket includes a base portion, a fastener attached to the base portion for securing to a reflex tube within the enclosure and a thermally conductive heat sink portion extending from the base portion. In further aspects, a loudspeaker assembly and an amplifier module incorporating the heat sink/mounting bracket are provided. In yet another aspect, a method of improving heat dissipation from an amplifier in a powered loudspeaker is also provided.

Description:
FIELD OF THE INVENTION 
   The present invention relates generally to audio speaker devices and more particularly to a heat sink apparatus for mounting electronic components within an audio speaker as well as methods, electronic assemblies, and loudspeakers employing the same. 
   BACKGROUND OF THE INVENTION 
   Powered audio speaker devices including on-board amplification circuitry for receiving, amplifying, and audibly reproducing an audio signal are used in connection with a variety audio applications, including home and studio audio systems, musical instrument amplification, public address systems, sound reinforcement, and the like. 
   Such devices generate significant thermal energy which, if not removed, may prevent proper functioning of the device or limit the lifetime of the device. Commonly, heat sinks are disposed so as to provide convective cooling with ambient air, e.g., by placement of the heat sink on an exterior surface of a speaker enclosure. While there are a number of devices which use a speaker cone as an air pump to provide air movement for cooling heat-producing components such as a speaker driver or power amplifier, such devices usually rely on a particular speaker or speaker enclosure design, such a specific speaker frame and/or speaker magnet assembly, or highly specialized speaker enclosure components, and cannot be adapted existing speakers or speaker designs. Therefore, it would be desirable to provide a heat dissipating mounting bracket which may be adapted for use in a variety of speakers or speaker designs without the need for a specialized speaker or enclosure. 
   Accordingly, the present invention contemplates a new and improved heat sink apparatus and method which overcome the above-referenced problems and others. 
   SUMMARY OF THE INVENTION 
   In a first aspect, a loudspeaker assembly includes an enclosure defining a speaker cavity and at least one speaker mounted in the enclosure. The enclosure has an opening formed in a surface thereof and a reflex tube extending from the opening into the speaker cavity, wherein the opening and reflex tube define a passageway for air movement in response to speaker movement. A combined heat sink and amplifier mounting bracket is secured to the reflex tube, the combined heat sink and amplifier mounting bracket including an amplifier mounting portion and a thermally conductive heat sink portion. The thermally conductive heat sink portion aligned with the reflex tube such that air moved in response to speaker movement passes over the heat sink portion. 
   In a second aspect, a combined heat sink and mounting bracket for a powered loudspeaker of a ported reflex type is provided. The combined heat sink and mounting bracket includes a base portion, a fastener attached to the base portion for securing to a reflex tube within the enclosure and a thermally conductive heat sink portion extending from the base portion. 
   In a third aspect, a combined heat sink and amplifier module for a powered loudspeaker includes a base portion and a fastener attached to the base portion for securing the combined heat sink and mounting bracket to the tube. A thermally conductive heat sink portion extends from the base portion and an amplifier is mounted to the base portion. The amplifier includes a heat-producing component, which is thermally coupled to the thermally conductive heat sink portion. 
   In a fourth aspect, a method for improving heat dissipation from an amplifier in a powered loudspeaker device includes positioning a combined heat sink and mounting bracket in the speaker cavity in alignment with the reflex tube and securing the combined heat sink and mounting bracket to the tube. An amplifier is mounted to the combined heat sink and mounting bracket, the amplifier being electrically coupled to the speaker. A heat producing component of the amplifier is thermally coupled to a heat sink portion of the combined heat sink and mounting bracket and the amplifier is operated to drive the speaker, wherein heat generated by the amplifier is transferred to the heat sink portion and wherein air movement through the reflex port exerts a cooling effect on the heat sink. 
   One advantage of the present invention resides in its ability to be adapted to a variety of ported reflex speakers or speaker enclosure designs, without reliance upon specialized speaker or speaker cabinet designs. 
   Still further advantages and benefits of the present invention will become apparent to those of ordinary skill in the art upon reading and understanding the following detailed description of the preferred embodiments. 

   
     BRIEF DESCRIPTION OF THE DRAWING 
     The invention may take form in various components and arrangements of components, and in various steps and arrangements of steps. The drawings are only for purposes of illustrating preferred embodiments and are not to be construed as limiting the invention. 
       FIG. 1  is a perspective view of a heat sink and bracket according to an exemplary embodiment the present invention; 
       FIG. 2  is a perspective view of the heat sink and bracket shown in  FIG. 1 , wherein the clamping arms shown in a circumferential arrangement for clamping to a reflex port of a speaker; 
       FIG. 3  is a front perspective view of an integrated amplifier and heat sink module according to an exemplary embodiment of the invention; 
       FIG. 4  is an exploded rear perspective view of the integrated amplifier and heat sink module shown in  FIG. 3 . 
       FIG. 5  is fragmentary view of an exemplary loudspeaker embodying the present invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring now to  FIGS. 1 and 2 , there appears an exemplary heat sink bracket  10  of the present invention. The heat sink bracket  10  includes mounting arms  12 , which are sufficiently flexible or bendable so that they may be wrapped around a reflex port of a ported or reflex loudspeaker, while still providing secure retention of bracket  12  thereon. The embodiment of  FIGS. 1 and 2  is adapted for use in connection with a loudspeaker having a ducted port cabinet or enclosure having at least one ducted port in which an opening  68  (see  FIG. 5 ) is provided in the cabinet, typically the front, side or back, in conjunction with a tube or duct extending from the opening into the interior of the enclosure. Often, the tube is a straight tube of circular cross-sectional shape and the present invention will be shown and described primarily by way of reference thereto. However, other tube configurations and cross-sectional shapes, such as oval or elliptical, polygonal, etc., and/or other tube geometries are also contemplated. 
   The mounting arms  12  include proximal ends  14  proximate a base  16 . Openings  18  near distal ends  20  of the mounting arms  12  receive a fastener for securing the arms  12  about a reflex port extending within a speaker enclosure. The fastener is depicted as a threaded connector  22 , such as a bolt, screw, or the like, engaging an internally threaded member  24 , such as a nut or the like (or internal threads within the opening  18 ), for securing the arms  12  and tightening the arms  12  about a reflex port. By selecting an appropriate length of the arms  12  and/or the position of the hole  18  placement thereon, the invention  10  may adapted for ports of any diameter. Likewise, a series of holes  18  may be placed along one or both of the arms  12  so that the unit may accommodate more than one port diameter. 
   The depicted embodiment includes clamping arms ( 12 ) connected by a threaded connector ( 22 ,  24 ), however, it will be recognized that other mechanical fastener types may be used in place thereof. Such alternative fasteners include but are not limited to one or more screws, clips, dogs, pawls, clamps, buckles, ties, bands, retaining rings, snap rings, adhesives, snap-fit, friction-fit, or sliding-fit members, sleeves, ties, bands, band clamps such as worm gear-tensioned or threaded rod-tensioned band clamps, spring-type or constant tension hose type clamps, and so forth. In still further embodiments, one or more features such as a mounting boss, threads, or other feature may be provided on the reflex tube for engaging a complimentary feature formed on the combined bracket and heat sink  10 . 
   The base  16  extends from the distal ends  14  of the arms  12 , in the inward direction relative to the opening  72  (see  FIG. 5 ) when the unit is placed in its operative position and secured to a duct  70  (see  FIG. 5 ) of a ducted port. The base  16  may include openings  26  for mounting an amplifier or associated circuit components. A heat sink portion  30  extends upwardly (in the orientation shown) from the base  16  and includes a thermally conductive plate member  32 . The plate member  32  includes a lower edge  35  adjoining the base portion  16 . The plate member  32  further includes an upper edge  36  having includes a series of fins or wings  34  extending therefrom. Openings  38  may be provided in the plate portion  32  to facilitate securing an amplifier in heat transfer relation thereto. 
   In the depicted embodiment, the fingers  34  are angled along the edge  36  with respect to the plate  32 , with adjacent fingers  34  being angled toward opposite sides of the plate  32 . It will be recognized that other configurations of the heat sink  30  are possible, and will depend on the heat dissipation requirements of the selected amplifier to be cooled. For example, the fins  34  may be omitted, wherein the heat sink portion constitutes a generally planar member. In other embodiments, the fingers  34  may be replaced with fins of alternative configuration disposed on one or more peripheral edges of the plate  32 . In still further embodiments, a separately formed heat sink, may be thermally coupled to the thermally conductive plate  32 , for example, to a surface of the conductive plate opposite the surface to which the amplifier contacts the plate  32 . Examples of such heat sinks include, but are not limited to, extruded, stamped, cast, machined, folded fin, and bonded fin heat sinks, and so forth, having heat dissipating members in any of a variety of known configurations, including fins, channels, cross cut channels, fingers, pins, and the like. 
   The plate member is generally planar and, in operation, may be generally aligned with the axial direction of the speaker port. As best seen in the embodiment of  FIG. 5 , the heat sink portion  30  is positioned next to the opening  72  of the reflex duct  70  such that it is positioned within the air stream caused by movement of the speaker cone  62 . Both the heat generated by the amplifier and the magnitude of speaker cone travel increase as the amplifier output is increased, thus moving a larger volume of air. In this manner, the cooling is self-regulating, being a function of amplifier output. 
   The heat sink portion  30 , and preferably the entire bracket  10 , may be formed from any thermally conductive material, such as a metal or metal alloy, preferably aluminum or an aluminum alloy. Other thermally conductive materials include copper or copper alloy, zinc or zinc alloy, beryllium or beryllium alloy, brass, stainless steel, and the like. The bracket  10  may be formed by first forming a flat, thermally conductive blank of desired outline followed by bending the shaped, flat blank to the final three-dimensional shape. The blank may be formed via casting, forging, stamping, cutting, machining, drilling, etc., and is preferably formed from a thermally conductive sheet material. The flat blank may then be bent along the lower and upper edges  35  and  36  to its final shape via an anvil, press, bending jig, or the like. The mounting arms  12  may be pre-bent to an approximate desired radius, or, may be bent by a user at the time of installation. 
   Referring now to  FIGS. 3 and 4 , there is shown an electronic assembly comprising a heat sink mounting bracket  10  having amplifier circuit or module  40  mounted thereto. The amplifier module includes a substrate  42 , preferably a printed circuit board substrate, such as a conventional copper-clad fiberglass epoxy laminate, or the like. An amplifier circuit  44 , which may be an integrated circuit package, is electrically coupled to the substrate, and any additional circuit components carried thereon, via lead wires  46 . 
   In the depicted embodiment, the substrate  42  may carry additional circuit components, such as power supply connectors, terminal connectors, fuses or other overload protection, and the like. It will be recognized, however, that components such as these and others may be mounted elsewhere in the speaker enclosure and/or may be omitted, depending on the speaker design or component types employed. 
   The amplifier circuit  44  is in thermal contact with the plate member  32  of the heat sink  30 , which acts to remove heat from the amplifier device  44 . As used herein, the term heat sink is understood to include not only the heat removing device itself, but also any optional thermal compound or material  48  (see  FIG. 2 ) interfacing with the amplifier  44  to effect efficient thermal transfer. Such thermal compounds may include, for example, thermal grease, thermal tape, thermal pads, thermal film, thermal epoxy, phase change thermal interface materials, and the like. Commonly, high-powered semiconductor devices or packaging contain a thermally conductive side or surface  50 , which is placed in contact with the plate member  32 . One or more threaded fasteners/screws  52  or other suitable affixing mechanisms, such as one or more clips, clamps, dogs, pawls, or the like, may be used to provide positive mechanical pressure between the amplifier package  44  and the heat sink plate member  32 , thereby providing firm thermal contact therebetween. 
   In the illustrated example, the substrate  42  is secured to the base portion  16  of the heat sink  10 , via threaded fasteners screws  54  or other suitable affixing mechanism. Spacers  56  may also be provided, for example, to prevent an over-tightening of the screws  54  or damaging the circuit board  42 . In the illustrated example, the spacers are formed of an insulating material to prevent inadvertent grounding of the amplifier  44 . Additional holes may provided to accommodate amplifiers and/or circuit boards of different sizes, shapes, or hole patterns. 
   Although the illustrated embodiment depicts an integrated circuit amplifier package  44 , it will be recognized that the heat sink bracket  10  of the present invention may also be employed in connection with an amplifier having discrete circuit components. For example, an amplifier circuit having one or more discrete power transistors may be employed. If employed, such power transistors may also be thermally coupled to the plate member  32  in the same manner as described above. 
   Referring now to  FIG. 5 , an exemplary loudspeaker  60  of the ported reflex type includes a first speaker  62  and a second speaker  64 , mounted within a ported enclosure  66 . The ported enclosure  66  includes an opening  68  therethrough and a tube or duct  70  extending inwardly into the enclosure  66  therefrom. The duct terminates in an opening  72  opposite the opening  68 . A heat sink bracket  10  is clamped to the port  70  via clamping arms  12  as described above. The heat sink bracket  10  carries an amplifier module  40 , including a circuit board  42  affixed to the base portion  16  of the bracket  10 , with an amplifier  44  being in thermal communication with thermally conductive plate  32  of a heat sink portion  30  of the bracket  10 . Fins  34  extend from the plate  32 . The heat sink portion  30  comprising the plate  32  and the fins  34  and is axially aligned with the tube  70  and positioned near the tube opening  72  such that air movement through the port  70  in response to movement of the speaker  62  will provide cooling of the heat sink  30 . 
   In the depicted embodiment, loudspeaker  60  is depicted as a two-way speaker system wherein the speaker  62  is a cone woofer designed to reproduce a lower frequency range and the speaker  64  is a tweeter for reproducing an upper frequency range. 
   It will be recognized that the present invention may be employed in connection with all manner of loudspeaker designs and speaker types, including any one or more electrodynamic speakers, electrostatic speakers, piezoelectric speakers, woofers, subwoofers, midrange speakers, tweeters, passive radiators, and so forth, or any combination thereof. 
   Additionally, it will be recognized that the loudspeaker may powered via an external power source, e.g., AC mains, generator, an electrical system of a vehicle, etc., or, via a self-contained power source, such as an internal battery or battery pack. 
   In a preferred embodiment, the loudspeaker  60  receives an analog audio signal via a cabled connection to an audio source and utilizes an analog audio amplifier. In alternative embodiments, a loudspeaker including a wireless receiver for receiving an audio signal modulated on a carrier wave (e.g., radio frequency, infrared, etc.) is also contemplated. 
   It will be recognized that any combination of an analog or digital input signal and an analog or digital amplifier may be employed. For example, the loudspeaker  60  may include an analog-to-digital converter for receiving an analog audio signal and a digital signal processor to provide digital filtering and/or other digital processing techniques for providing control over audio signals. For example, digital signal processing may be utilized in lieu of traditional analog crossover networks to separate audio signals into low frequency and high frequency bands. 
   In certain embodiments, a digital amplifier may be provided for receiving digital audio data, e.g., directly from a digital storage medium or source, via streaming data containing digital audio data, or from an analog audio source using an analog-to-digital converter. 
   Similarly, a digital-to-analog converter may be provided for receiving a digital or digitally processed signal and outputting an analog signal to an analog amplifier. 
   Likewise, the use of multiple or multichannel amplifiers are also contemplated. For example, a multiple channel amplifier (or multiple amplifiers) may be employed for biamplified or triamplified systems, e.g., wherein different frequency bands are separately amplified. Also, a multichannel amplifier (or multiple amplifiers) may be provided to receive and separately amplify individual channels of a multichannel audio signal. For example, a pair of loudspeakers may be provided for audibly reproducing a stereophonic audio signal wherein one of the loudspeakers is powered and the other is not. In this manner, both channels are amplified by the powered loudspeaker and one of the channels is output to the nonpowered loudspeaker. 
   The invention has been described with reference to the preferred embodiments. Modifications and alterations will occur to others upon a reading and understanding of the preceding detailed description. It is intended that the invention be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.