Patent Publication Number: US-9841248-B2

Title: Heat dissipation assembly incorporated into a handguard surrounding a rifle barrel

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This Application claims the benefit of U.S. Provisional Application 62/171,303 filed on Jun. 5, 2015, the contents of which is incorporated herein in its entirety, 
    
    
     FIELD OF THE INVENTION 
     A rifle hand guard assembly incorporating heat dissipating structure in the form of a thermo-electric generator utilizing a Seebeck module arranged between a heat sink and cooling block and which absorbs heat emanating from the rifle barrel. In a first variant, the module powers a piezoelectric blower which in turn integrates an inner diaphragm, piezoelectric element and pump in order to create an airflow through a nozzle for in turn driving a circular air blade integrated into an elongated tube mounted over the rifle barrel. 
     In a second variant, a fan is substituted for the piezo-electric blower and the circular blade substituted by a vortex effect created by intake flow patterns created by the fan which facilitates wicking away of heat from the barrel, via the handguard incorporated hot plate to the exteriorly supported cooling plates. An air tube is attached directly to an interior of the handguard, in abutting contact with the barrel nut. The air tube exhibits a plurality of slot configured on its abutting end face which causes the airflow to be rotated and compressed in a torsionally directed fashion around the barrel separate from the heat transfer from the barrel nut to the hot plate. 
     In operation, the assembly converts the emanating heat from the barrel to either of the piezo-blower operated rotary fan or air blade, which operates to both discharge heat emanating from the barrel as well as to draw, via forced convention in the one variant or torsionally generated airflow in the other variant, a cooling airflow to assist in preventing overheating of the barrel. Air intake vents formed in the hand guard overlap the fins for assisting in convection resulting from pulling of the cooling air over the fins. 
     BACKGROUND OF THE INVENTION 
     The prior art is documented with examples of heat dissipation, or heat sinking, assemblies for use with a firearm barrel. As is known, repeated discharge of rounds in either of semi-automatic or automatic firing modes results in rapid heating of the barrel to an excessive degree, resulting in the requirement to provide for cooling of the barrel to prevent damage or a misfiring condition. 
     A first example is disclosed in the heat sink rail system of Lee, US 2014/0082990 which teaches passing air through fins configured in the rail system, such further adapted for mounting other accessories. The fins can be configured either axially along the barrel or in either of inwardly or outwardly extending fashion relative to the rail system. 
     A further example is shown in Samson, U.S. Pat. No. 8,448,367 which teaches a modular fore-end rail assembly for mounting onto a firearm which includes a hand guard and a bushing element that combines with an end portion of the hand guard to encircle a standard barrel nut. The material construction facilitates heat transfer from the barrel nut to the hand guard at an adjusted rate such that rapid changing of the bushing elements changes the heat rate of the hand guard. 
     Other relevant examples include each of the firearm heat sink of Muirhead, U.S. Pat. No. 6,508,159, the heat removal system of Larson, U.S. Pat. No. 6,827,130, the fin-type heat exchanger of Price, WO 84/04432, the universal barrel nut for a firearm of Mueller, U.S. Pat. No. 8,726,559, and the heat exchanger barrel nut of Davies et al., U.S. Pat. No. 7,464,496. 
     SUMMARY OF THE INVENTION 
     As previously described, the present invention discloses a rifle hand guard assembly incorporating heat dissipating structure in the form of a thermo-electric generator utilizing a Seebeck module arranged between heat sink and cooling block aspects of a handguard and associated barrel nut for absorbing heat emanating from the rifle barrel. In a first variant, the module powers a piezoelectric blower which in turn integrates an inner diaphragm, piezoelectric element and pump in order to create an airflow through a nozzle for in turn driving a circular air blade integrated into an elongated tube mounted over the rifle barrel. 
     In a second variant, a fan is substituted for the piezo-electric blower and the circular blade substituted by a vortex effect created by intake flow patterns created by the fan which facilitates wicking away of heat from the barrel, via the handguard incorporated hot plate to exteriorly supported cooling plates. An air tube is attached directly to an interior of the handguard, in abutting contact with the barrel nut. The air tube exhibits a plurality of slot configured on its abutting end face which causes the airflow to be rotated and compressed in a torsionally directed fashion around the barrel separate from the heat transfer from the barrel nut to the hot plate. 
     In operation, the assembly converts the emanating heat from the barrel to either of the piezo-blower operated rotary fan or air blade, which operates to both discharge heat emanating from the barrel as well as to draw, via forced convention in the one variant or torsionally generated airflow in the other variant, a cooling airflow to assist in preventing overheating of the barrel. Air intake vents formed in the hand guard overlap the fins for assisting in convection resulting from pulling of the cooling air over the fins. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Reference will now be made to the attached drawings, when read in combination with the following detailed description, wherein like reference numerals refer to like parts throughout the several views, and in which: 
         FIG. 1  is a cutaway end view of a concentric arrangement of an end mounted barrel nut associated with a first embodiment the present assembly and including an inner most aluminum heat sink layer, intermediate Seebeck Module layer and outermost cooling block layer incorporating circumferentially arrayed pluralities of ventilation holes and heat dissipation fins; 
         FIG. 2  is a rotated end view of the barrel nut; 
         FIG. 3  is an assembly view of the elongated hand guard and barrel nut with interposed piezoelectric blower and circular air knife and further depicting the arrangement of air intake vents overlapping the finned cooling block; 
         FIG. 4  is a cutaway view of the circular air knife in  FIG. 3  and better illustrating the dual inward direction of the cooling airflows generated by the piezoelectric blower; 
         FIG. 5  is a ninety degree rotated and lengthwise cutaway of  FIG. 3  and which illustrates the arrangement of components contained within each of elongated handguard, cooling block and end situated aluminum barrel nut; 
         FIG. 6  is a sectional illustration of the internal air knife and piezoelectric blower; 
         FIG. 7  is an environmental illustration of a free floating handguard associated with an AR-15 rifle according to one non-limiting variant of the present inventions; 
         FIG. 8  is a disassembled illustration of the free float hand guard and illustrating the two piece construction of the barrel nut and free float tube with knurled exterior surface; 
         FIG. 9  is a perspective of a variation of barrel nut with ventilation hole pattern and annular extending nose; 
         FIG. 10  is a succeeding end view perspective illustration to  FIG. 9  of the barrel nut and barrel for attachment of the thermoelectric generator; 
         FIG. 11  is an illustration of a non-limiting variant of annular arrayed cooling fins which can be integrated into the cooling block; 
         FIG. 12  is a partial cutaway view in sectional perspective of a Seebeck Module associated with the thermoelectric generator; 
         FIG. 13  illustrates a Seebeck Module type piezoelectric blower incorporated into the present assembly; 
         FIGS. 14-15  illustrate perspective and side cutaway views of the piezoelectric element, pump and air knife nozzle; 
         FIG. 16  is a partially exploded perspective of a hand guard assembly according to a second non-limiting embodiment incorporating heat dissipating aspects; 
         FIG. 17  is an enlarged exploded perspective of the hand guard integrated into the assembly and including each of a customized barrel nut, handguard integrated hot plate, thermoelectric generator (TEG), outer cooling fins/plates, TEG operated fan and interiorly positioned and barrel nut abutting air tube for facilitating torsionally induced airflow over and along the barrel; 
         FIG. 18  is a first cross sectional cutaway taken along line  18 - 18  of  FIG. 16  and depicting the arrangement of the interiorly positioned hot plate, thermoelectric generator, and outer cooling fins or plate; 
         FIG. 19  is a second cross sectional cutaway taken along line  19 - 19  of  FIG. 16  and showing the TEG activated fan for drawing air in through the cooling block and subsequently redirecting fluid flow in a compressed and torsional/winding manner through the slots configured in the air tube and across the barrel; and 
         FIG. 20  is a reverse side perspective of the hand guard assembly removed from the barrel and depicting the wires extending from the thermoelectric generator for operating the fan. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     As previously described, the present invention discloses a rifle hand guard assembly incorporating heat dissipating structure, such as in the form of a thermo-electric generator utilizing a Seebeck module arranged between a heat sink and cooling block and which absorbs heat emanating from the rifle barrel. As will be further described with reference to the appended illustrations, the module powers a piezoelectric blower which in turn integrates an inner diaphragm, piezoelectric element and pump in order to create an airflow through a nozzle for in turn driving a circular air blade integrated into an elongated tube mounted over the rifle barrel. 
     The tube (also termed a free floating handguard) is mounted in thermally conducting fashion with the rifle barrel and is in contact with cooling fins arranged on an end assembled cooling block, the fins being arrayed in circumferential and linearly extending fashion around an attached barrel nut for converting the emanating heat from the barrel to a redirected cooling airflow to assist in preventing overheating of the barrel. Air intake vents formed in the hand guard overlap the fins for assisting in forced convection resulting from pulling of the cooling air over the fins. 
     Referring initially to  FIGS. 1-6 , a series of diagrammatic views are shown of one non-limiting hand guard assembly incorporating thermoelectric generation technology for converting the heat emanating of the rifle barrel into an electrical output for driving a piezoelectric blower for in turn rotating a circular blade integrated into the free float tube and in order to provide constant cooling of the barrel. Without limitation, the present invention contemplates a hand guard assembly which can be configured for mounting over a variety of different firearms. Both the free float tube  10  and barrel nut  12  can be constructed of any suitable heat dissipating and conducting materials, such as aluminum. 
     As best shown in each of  FIGS. 5 and 8 , the assembly according to the illustrated embodiment includes an elongated and free float tube  10  and an end attachable barrel nut  12 , each typically incorporating a generally polygonal or circular shape in cross section and which is configured to include inner apertures for mounting about the barrel (at  2  in  FIG. 5 ) of the firearm. Although not clearly shown, the free float tube  10  also incorporates a circular air knife  14  (also termed a rotatable blade) at a proximal end thereof in proximity to the end-attachable barrel nut  12 . To this end, reference to known air blade designs (such as incorporated into conventional vacuum cleaners) is referenced in  FIG. 16  and which is capable of being integrated into the free float tube for maximizing a desired rotational speed and airflow generated output in response to the piezo-element generated blower input. 
     A pair of piezoelectric blowers  16  and  18  are illustrated arranged at opposing circumferential access locations in the tube  10  (see again  FIG. 5 ) in which the blowers direct concentrated airflows, via their nozzles, for jointly rotating the circular air knife blades. Additional features associated with the barrel nut  12  include a circumferentially extending array of ventilation holes  20  in combination with a likewise circumferentially extending array of cooling block fins  22 . As further depicted in  FIG. 3 , a further plurality of air intake vents  24  are arranged about the circumference of the barrel nut  12  and which overlap the fins  22  of the cooling block, this in order to enhance the forced convection which occurs upon the cool air being pulled over the fins  22  in a radiator like fashion. 
       FIG. 1  further illustrates in cutaway end view a concentric arrangement of the end mounted barrel nut  12  associated with the present assembly and including an inner most aluminum heat sink layer  26 , intermediate Seebeck Module layer  28  and outermost cooling block layer incorporating the circumferentially arrayed pluralities of ventilation holes  20  and heat dissipation fins  22 .  FIG. 2  is a rotated end view of the barrel nut  12  and better depicting the arrangement of the cooling block fins  22  relative to the base portion of the end nut  12 , within which are configured the ventilation holes  20 . 
       FIG. 3  is an assembly view of the elongated hand guard  10  and barrel nut  12  with interposed piezoelectric blowers  16 / 18  and circular air knife  14  and further depicting the arrangement of air intake vents  24  overlapping the finned cooling block.  FIG. 4  is a cutaway view of the circular air knife in  FIG. 3  and better illustrating the dual inward direction of the cooling airflows generated by the piezoelectric blowers  16  and  18  according to one non-limiting arrangement which further contemplates any number or arrangement of piezoelectric blowers in any configuration desired.  FIG. 5  is a ninety degree rotated and lengthwise cutaway of  FIG. 3  and which illustrates the arrangement of components contained within each of elongated handguard, cooling block and end situated aluminum barrel nut, with  FIG. 6  providing a sectional illustration of the internal air knife  14  and piezoelectric blower  16 / 18 . 
     With further reference to the environmental illustration of  FIG. 7 , a free floating handguard assembly is shown associated with an AR-15 rifle according to one non-limiting variant of the present inventions. This again includes a main tubular body  10  with innermost heat sink layer overlaying the barrel  2  of the conventional rifle  4 , as well as the threaded end nut  12  attached to the proximal end of the body  10  and which exhibits the circumferential array of ventilation holes  20  disposed about a communicating rear end of the nut for venting the heat generated by the barrel. 
       FIG. 8  is a disassembled illustration of the free float hand guard and illustrating the two piece construction of the barrel nut  12  and free float tube  10 , such further exhibiting a knurled exterior surface  30 . Not clearly shown is the internal rotating air blade which is configured within the tube  10  in a manner and location consistent with the schematic cutaway of  FIG. 5 . Also shown in  FIG. 8  with regard to the bearing nut  12  is the circumferential array of ventilation holes  20  as well as the threaded annular side  32 , this rotatably inter-engaging with mating threads associated with a given engaging end of the tube  10 . 
       FIG. 9  is a perspective of a variation of barrel nut  12 ′ with ventilation hole pattern, again at  20 , and an annular extending nose or lip  34 . A plurality of threads  36  are further depicted upon an interior annular wall of the nut  12 ′ for inter-engaging a suitably configured end of the main tube  10 . 
       FIG. 10  is a succeeding illustration to  FIG. 9  of the mounting location  38  for receiving the thermoelectric generator attached to the barrel nut  12 ′. As is known, a thermoelectric generator (also called a Seebeck generator) is a device which converts heat (defined as a temperature differential) directly into electrical energy, this utilizing a phenomenon called the Seebeck effect which operates under the principle that a thermal gradient famed between two dissimilar conductors produces a voltage. 
       FIG. 11  is an illustration of a non-limiting variant of annular arrayed cooling fins, such as previously depicted at  22 , and which can be integrated into the cooling block. As previously described with reference to the diagrammatic views of  FIGS. 1-6 , the fins  22  assist in drawing the heat generated by the rifle barrel  2 , via the inner aluminum heat sink layer  26 . 
       FIG. 12  is a partial cutaway view in sectional perspective of a Seebeck Module, such as associated with layer  28  in  FIG. 1 , associated with the thermoelectric generator. As shown, this module creates the heat engine between the heat sink and cooling block and includes upper  40  and lower  42  ceramic substrate layers. Alternating N-type  44  and P-type  46  are arrayed in grid supported fashion upon conductor tabs  48  arranged between the substrate layers  40  and  42 , with positive  50  and negative  52  leads extending to electrically communicating edge locations of the module  28 . 
     As previously described, the Seebeck effect is used in thermoelectric generators, which function like heat engines, but are less bulky, have no moving parts, and are typically more expensive and less efficient. The thermoelectric effect is the direct conversion of temperature differences to electric voltage and vice versa. 
     As is also known, a thermoelectric device creates voltage when there is a different temperature on each side. Conversely, when a voltage is applied to it, it creates a temperature difference. At the atomic scale, an applied temperature gradient causes charge carriers in the material to diffuse from the hot side to the cold side. This effect can be used to generate electricity, measure temperature or change the temperature of objects. Because the direction of heating and cooling is determined by the polarity of the applied voltage, thermoelectric devices can also be used as temperature controllers. 
     With the above explanation,  FIG. 13  further illustrates a piezoelectric blower, such as previously shown at  16 / 18  in the diagrammatic views of  FIGS. 1-6 , incorporated into a circuit board  54  with processor  55  and associated support components. In this fashion, the thermoelectric generating barrel nut ( 12  or  12 ′) powers each of the piezoelectric blowers utilized. 
       FIGS. 14-15  illustrate perspective and side cutaway views of the piezoelectric element, pump and air knife nozzle, all of which are incorporated into a subset assembly  56  in communication with the board assembly  54  of  FIG. 13 , the assemblies  56  each being arrayed in the manner depicted diagrammatically at  16  and  18  in  FIG. 1-6 . As best shown in the side cutaway assembly of  FIG. 15 , a piezoelectric element  58  is integrated into an interior of a generally three dimensional square or rectangular shaped housing  60  and forms a part of an inner diaphragm  62 , in turn creating an inner pump  64 . 
     Applying the Seebeck effect principles previously described, an airflow is created in an intake channel  66  which collects and accelerates the interior airflow for delivery through upper end nozzles  68 . An intake replacement airflow is further created by drawing through the air intake vents  24  of  FIG. 3  which are again understood to overlap the finned cooling block portion of the barrel nut and, in this fashion, creates a forced convection affect by pulling the cool intake air over the fins in a radiator like fashion. As further previously described, the piezoelectric blowers are arranged in any desired pattern around the periphery of the outer hand guard in proximity to the circular rotating air blade which is supported within the interior of the free float tube  10  at the engagement location with the barrel nut  12 . 
     Referring collectively to  FIGS. 16-20 , and initially to  FIG. 16 , a partially exploded perspective is shown at  70  of a hand guard assembly according to a second non-limiting embodiment incorporating heat dissipating aspects. Along with the enlarged exploded perspective of  FIG. 17 , the assembly  70  includes a hand guard body  72  exhibiting a generally cylindrical and elongated body and further depicting an upper mounting rail  74 , such further referenced as a Picatinny style rail. 
     As further best shown in  FIG. 17 , the hand guard body  72  includes pluralities of inner perimeter defined apertures  76 ,  78 ,  80 , et seq. formed in spaced fashion along its length, and further such as in distributed arrangement along each of octagonal style interconnected sides as further depicted in cross section. Additional perimeter defined apertures are further shown at  80 ,  82 ,  84  extending in spaced fashion along a mounting neck  86  underneath the uppermost mounting rail  74 . Without limitation, the shape and configuration of the handguard can be modified from that shown and which is illustrative only of one possible embodiment of its design. 
     A customized (typically aluminum) barrel nut  88  is provided for securing the firearm barrel, further shown at  90  in this variant, to the firearm upper receiver (not shown). The barrel nut  88  includes an circumferentially projecting forward end  90  and attaches to the handguard body  72  for securing the same to the upper receiver. As further shown, the barrel nut can include additional aperture patterns in circumferentially distributed fashion along either of its main body  88  or integrated forward projecting end  90 . 
     The handguard body, see as depicted at location  92 , is typically constructed of a metal for collecting the heat of the barrel nut  88 , via conductivity, and further operates as a hot side for driving a reconfigured thermoelectric generator (TEG)  94 , similar to that depicted at  28  in  FIG. 12 . As shown in  FIG. 20 , such generators are typically provided in paired fashion at opposite rear proximate sides of the handguard in proximity to the barrel nut  88 , the TEGs  94  each including a pair of wires  96  and  98  in communication with and for driving one or more fan components  100 . 
     The fan component  100  is seated within a pocket configured within a finned cooling block  102  exhibited on an upper first side of the handguard  72  (see opposite lower side cooling block  104  with fins in  FIG. 20 ). As understood, the cooling blocks  102 / 104  integrate elongated apertures, between which are positioned the finned surfaces of the blocks, and which are in communication with the interior pockets within which the fan components  100  are seated, In this fashion and, upon activation of the fan by the wires extending from the TEG, this causes the drawing in of air flow through the cooling block fins which is then communicated to the handguard interior via the slots  76 ,  78 ,  80  et seq. configured therethrough. 
     A pair of cooling plates  106  and  108  are also provided, each including in the non-limiting depicted embodiment a multi-sided (such as shown by three sided) and inter-angled configuration which is mounted to an exterior surface location (see at  110  in  FIG. 17 ) of the handguard  72  via screws (at  112 ). The finned cooling blocks  102 / 104  and cooling plates  106 / 108  are examples of cooling elements located upon the exterior of handguard and it is envisioned that these can be reconfigured or repositioned as desired. As further shown, additional screws (at  114 ) are likewise provided for securing a base location (see at  116  for specific cooling block  102  in  FIG. 17 ) of each upper side or lower side positioned cooling block  102  or  104 , and for mounting the same to the handguard in proximate forward position relative to the cooling plates. 
     An air tube  118  is provided which is secured within the interior of the handguard body  72  in abutting fashion against a forward end of the barrel nut  88 . The air tube includes an annular projecting inner end  120 , this further integrating an arcuate side extending passageway  122  which aligns underneath with the fan component  100 . Additional torsionally directed airflow passageways are further configured within the air tube  118  (see as represented at  124 ,  126 ,  128 , et. seq.) these being in communication with the side disposed air passageway  122 . 
     As best shown in  FIG. 19 , and upon activation of the fan component  100  by the TEG  94 , in order to draw airflow into the handguard via the finned cooling blocks  104 , the slot configuration in the air tube is configured to compress and drive airflow through the air tube in a vortex fashion (see air patterns  130 ,  132 , et seq.). The winding and torsionally directed air flow is directed around and along the barrel  90  in a manner which maximized wicking away of heat from the barrel, such being further vented through the apertures  76 ,  78 ,  80 , et seq. of the handguard (see additional outflow patterns  134 ,  136 , et seq.). 
     As previously indicated, the air tube  118  abuts the barrel nut  88  and provides an aspect of heat dissipation additional and separate from that effectuated by the heat transfer from the barrel nut to the hand guard hot plate portion  92 . It is also envisioned that variants of the invention can modify the heat dissipating aspects of either the direct barrel nut to cooling block conductivity component or TEG-to-fan-to air tube convection component, the present inventions featuring both aspects in a preferred embodiment however which can also be provided separately. 
     Having described my invention, other and additional preferred embodiments will become apparent to those skilled in the art to which it pertains, and without deviating from the scope of the appended claims. This can include reconfiguring the handguard to integrate many of the aspects of the interiorly positioned air tube into a single article, as well as revising the shape, location and/or arrangement of any one or more of the of the cooling fins, thermoelectric generator and vortex airflow inducing fan. It is also envisioned that the definition of the hot side (see again portion  92 ) of the handguard can be modified from that shown in order to provide other mechanisms for effectuating direct heat dissipating conductivity to the handguard exterior.