Patent Publication Number: US-10328623-B2

Title: Actuator cooling apparatus and method

Description:
RELATED APPLICATIONS 
     This application is a continuation of and claims the benefit of priority to U.S. application Ser. No. 14/459,622 filed Aug. 14, 2014, which is a continuation-in-part of and claims the benefit of priority to U.S. international application Serial no. PCT/US14/39932 filed May 29, 2014 which claims priority to U.S. Provisional application Ser. No. 61/828,391 filed May 29, 2013, the disclosures of the foregoing of which are incorporated by reference in their entirety as if fully set forth herein. 
     This application is also a continuation-in-part of and claims the benefit of priority to U.S. application Ser. No. 13/484,336 filed May 31, 2012 which is a continuation of PCT/US2011/062099 filed Nov. 23, 2011, the disclosures of both of the foregoing are incorporated by reference in their entirety as if fully set forth herein. 
     This application is also a continuation-in-part of and claims the benefit of priority to U.S. application Ser. No. 13/484,408 filed May 31, 2012 which is a continuation of PCT/US2011/062096 filed Nov. 23, 2011, the disclosures of both of the foregoing are incorporated by reference in their entirety as if fully set forth herein. 
     This application is also a continuation-in-part of and claims the benefit of priority to PCT/US2012/067379 (publication no WO 2014/025369) filed Nov. 30, 2012, the disclosure of which is incorporated by reference in its entirety as if fully set forth herein. 
     This application is also a continuation-in-part of and claims the benefit of priority to PCT/US13/053591 (publication no WO 2014/025674) filed Aug. 5, 2013, the disclosure of which is incorporated by reference in its entirety as if fully set forth herein. 
     The disclosures of all of the following are incorporated by reference in their entirety as if fully set forth herein: U.S. Pat. Nos. 5,894,025, 6,062,840, 6,294,122, 6,309,208, 6,287,107, 6,343,921, 6,343,922, 6,254,377, 6,261,075, 6,361,300, 6,419,870, 6,464,909, 6,599,116, 7,234,929, 7,419,62, 7,569,169, U.S. patent application Ser. No. 10/214,118, filed Aug. 8, 2002, U.S. Pat. No. 7,029,268, 7,270,537, 7,597,828, U.S. patent application Ser. No. 09/699,856 filed Oct. 30, 2000, U.S. patent application Ser. No. 10/269,927 filed Oct. 11, 2002, U.S. application Ser. No. 09/503,832 filed Feb. 15, 2000, U.S. application Ser. No. 09/656,846 filed Sep. 7, 2000, U.S. application Ser. No. 10/006,504 filed Dec. 3, 2001, U.S. application Ser. No. 10/101,278 filed Mar. 19, 2002 and PCT Application No. PCT/US11/062099 and PCT Application No. PCT/US11/062096, U.S. Pat. Nos. 8,562,336, 8,091,202 and 8,282,388. 
    
    
     BACKGROUND OF THE INVENTION 
     Injection molding systems have been developed employing mount mechanisms for actuators that are cooled via injection of water through water flow channels as shown for example in U.S. Pat. No. 8,562,336, the disclosure of which is incorporated herein by reference in its entirety as if fully set forth. 
     SUMMARY OF THE INVENTION 
     An injection molding apparatus comprising: 
     a heated manifold that receives an injection fluid material from an injection molding machine, the heated manifold routing the injection fluid to a fluid delivery channel that extends and delivers the injection fluid material under an injection pressure to a gate of a mold cavity, 
     an actuator comprising an actuator housing containing a drive member interconnected to a valve pin having a drive axis in an arrangement such that the valve pin is drivable along the axis through a selected stroke length between an upstream fully gate open position and a downstream gate closed position, 
     the actuator housing being mounted on an upstream surface of the heated manifold, a downstream end of the actuator housing being spaced a selectable distance upstream of the upstream surface forming a gap between the downstream end of the actuator housing and the upstream surface of the heated manifold, 
     the apparatus including one or more heat convectors each heat convector comprised of: 
     a heat conductive leg disposed within the gap and mounted in heat conductive communication with the heated manifold, and 
     a heat conductive arm extending distally upstream and away from the gap out of contact with the actuator housing such that heat is conducted from the leg to the arm upstream and away from the downstream end of the actuator housing. 
     The heat conductive leg of at least one of the one or more heat convectors is typically mounted in metal-to-metal heat conductive communication with the heated manifold. 
     The heat conductive arm of at least one of the one or heat convectors is preferably spaced radially apart from the actuator housing relative to the drive axis. 
     An upstream end of the heat conductive arm of at least one of the one or more heat convectors is preferably disposed in metal-to-metal heat conductive communication with a plate that is mounted in heat conductive isolation from the heated manifold. 
     The heat conductive arm of at least one of the one or more heat convectors can include a metal finger that is disposed in metal-to-metal contact under constant force with the plate. 
     The metal finger is typically slidably mounted on the arm in engagement with a spring, the metal finger being engagable in metal-to-metal contact with the plate under spring force exerted by the spring when compressed. 
     The apparatus typically further comprises a bushing mounted in metal-to-metal heat conductive contact with the heated manifold, the valve pin being slidably received within a guide channel of the bushing for reciprocally driven upstream-downstream movement along the drive axis of the valve pin, wherein at least one of the one or more heat convectors has a leg that is mounted in metal-to-metal heat conductive contact with the bushing. 
     The leg of at least one of the one or more heat convectors is preferably mounted in metal-to-metal heat conductive contact with the heated manifold. 
     The one or more heat convectors can comprise at least first and second heat convectors, each leg of each heat convector being mounted in metal-to-metal heat conductive communication with the heated manifold. 
     The heat conductive arm of at least one of the first and second heat convectors is typically spaced radially apart from the actuator housing relative to the drive axis. 
     An upstream end of the heat conductive arm of at least one of the first and second heat convectors is preferably disposed in metal-to-metal heat conductive communication with a plate that is mounted in heat conductive isolation from the heated manifold. 
     The apparatus typically further comprises a bushing mounted in metal-to-metal heat conductive contact with the heated manifold, the valve pin being slidably received within a guide channel of the bushing for reciprocally driven upstream-downstream movement along the drive axis of the valve pin, wherein the leg of at least one of first and second heat convectors is mounted in metal-to-metal heat conductive contact with the bushing. 
     The apparatus can further comprise an actuator mount that is mounted in metal-to-metal heat conductive contact with the heated manifold, wherein the leg of at least one of the one or more heat convectors is mounted in metal-to-metal heat conductive contact with the actuator mount. 
     The apparatus of typically further comprises an actuator mount that is mounted in metal-to-metal heat conductive contact with the heated manifold, wherein the leg of at least one of the first and second heat convectors is mounted in metal-to-metal heat conductive contact with the actuator mount. 
     The leg of at least one or more of the heat convectors can be mounted in metal to metal heat conductive contact with the actuator housing. 
     Typically the leg of at least one or more of the heat convectors is mounted in metal to metal heat conductive contact with an insulator or standoff that is mounted in heat conductive contact with the actuator housing. 
     The heat conductive arm of at least one of the one or more heat convectors can be spaced apart from the actuator housing extending along an axis or direction that is generally perpendicular to the drive axis. Alternatively the heat conductive arm of at least one of the one or more heat convectors can be spaced apart from the actuator housing extending along an axis or direction that is generally parallel to the drive axis. 
     In another aspect of the invention there is provided a method of performing an injection cycle with an injection molding apparatus that is comprised of: 
     a heated manifold containing a distribution channel that receives an injection fluid material from an injection molding machine, the heated manifold routing the injection fluid from the distribution channel to a fluid delivery channel that extends and delivers the injection fluid material under an injection pressure to a gate of a cavity of a mold, 
     an actuator comprising an actuator housing containing a drive member interconnected to a valve pin having a drive axis in an arrangement such that the valve pin is drivable along the axis through a selected stroke length between an upstream fully gate open position and a downstream gate closed position, 
     the actuator housing being mounted on an upstream surface of the heated manifold, a downstream end of the actuator housing being spaced a selectable distance upstream of the upstream surface forming a gap between the downstream end of the actuator housing and the upstream surface of the heated manifold, 
     the apparatus including one or more heat convectors each heat convector comprised of: 
     a heat conductive leg disposed within the gap and mounted in heat conductive communication with the heated manifold, and
         a heat conductive arm extending distally upstream and away from the gap such that heat is conducted from the leg to the arm upstream and away from the downstream end of the actuator housing,   the method comprising:   injecting a selected injection fluid from the injection molding machine into the distribution channel of the manifold under a pressure sufficient to route the injection fluid to the fluid delivery channel, and,   continuing to inject the injection fluid for a time sufficient to force the injection fluid to be routed into the cavity of the mold.       

     In such a method the one or more heat convectors preferably comprises at least first and second heat convectors, each leg of each heat convector being mounted in metal-to-metal heat conductive communication with the heated manifold. 
     In such a method the heat conductive arm of at least one of the first and second heat convectors is preferably spaced radially apart from the actuator housing relative to the drive axis. 
     In such a method an upstream end of the heat conductive arm of at least one of the first and second heat convectors is preferably disposed in metal-to-metal heat conductive communication with a plate that is mounted in heat conductive isolation from the heated manifold. 
     In another aspect of the invention there is provided an injection molding apparatus comprising: 
     a heated manifold that receives an injection fluid material from an injection molding machine, the heated manifold routing the injection fluid to a fluid delivery channel that extends and delivers the injection fluid material under an injection pressure to a gate of a mold cavity, 
     an actuator comprising an actuator housing containing a drive member interconnected to a valve pin having a drive axis in an arrangement such that the valve pin is drivable along the axis through a selected stroke length between an upstream fully gate open position and a downstream gate closed position, 
     the actuator housing being mounted on an upstream surface of the heated manifold, a downstream end of the actuator housing being spaced a selectable distance upstream of the upstream surface forming a gap between the downstream end of the actuator housing and the upstream surface of the heated manifold, 
     the apparatus including first and second heat convectors each heat convector comprised of: 
     a heat conductive leg disposed within the gap and mounted in heat conductive communication with the heated manifold, and 
     a heat conductive arm extending distally upstream and away from the gap out of contact with the actuator housing such that heat is conducted from the leg to the arm upstream and away from the downstream end of the actuator housing. 
     The heat conductive leg of at least one of the one or more heat convectors is typically mounted in metal-to-metal heat conductive communication with the heated manifold. 
     The heat conductive arm of at least one of the one or heat convectors is typically spaced radially apart from the actuator housing relative to the drive axis. 
     An upstream end of the heat conductive arm of at least one of the first and second heat convectors is typically disposed in metal-to-metal heat conductive communication with a plate that is mounted in heat conductive isolation from the heated manifold. 
     Such an apparatus preferably further comprises a bushing mounted in metal-to-metal heat conductive contact with the heated manifold, the valve pin being slidably received within a guide channel of the bushing for reciprocally driven upstream-downstream movement along the drive axis of the valve pin, wherein at least one of the first and second heat convectors has a leg that is mounted in metal-to-metal heat conductive contact with the bushing. 
     Such an apparatus typically further comprises an actuator mount that is mounted in metal-to-metal heat conductive contact with the heated manifold, wherein the leg of at least one of the first and second heat convectors is mounted in metal-to-metal heat conductive contact with the actuator mount. 
     Such an apparatus typically further comprises an actuator mount that is mounted in metal-to-metal heat conductive contact with the heated manifold, wherein the leg of at least one of the first and second heat convectors is mounted in metal-to-metal heat conductive contact with the actuator mount. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and further advantages of the invention may be better understood by referring to the following description in conjunction with the accompanying drawings in which: 
         FIG. 1  is a top perspective view of a pair of actuators mounted on a heated manifold or hotrunner, each actuator having housings and heat convectors mounted in an arrangement according to one embodiment of the invention. 
         FIG. 2  is a front side view of one of the actuators of the  FIG. 1  system mounted to the manifold in conjunction with a first exemplary embodiment of heat convectors according to the invention. 
         FIG. 2A  is a sectional view taken along lines  2 A- 2 A of  FIG. 2 . 
         FIG. 2B  is a sectional view taken along lines  2 B- 2 B of  FIG. 2 . 
         FIG. 2C  is view similar to  FIG. 2B  showing the actuator mounted on a hotrunner or heated manifold and showing a top clamping plate assembled together with the apparatus and the heat convective arm of one of the heat convectors of the apparatus in spring-loaded metal-to-metal contact with the top clamping plate. 
         FIG. 2CC  is an enlarged fragmentary detail view of a portion of  FIG. 2 . 
       FIG.  2 CCC is a fragmentary cross-sectional view similar to  FIG. 2CC  but showing an alternate embodiment of a heat convector arranged along an axis perpendicular P to the drive axis A. 
         FIG. 2D  is a rear side view of the  FIG. 2  actuator. 
         FIG. 2E  is a right side view of the  FIG. 2  actuator. 
         FIG. 2F  is a top perspective view of one of the two heat convectors of the  FIG. 2  apparatus that mounts to the valve pin guide bushing and includes a spring-loaded finger mounted to the arm portion of the convector. 
         FIG. 2G  is a top perspective view of another one of the two heat convectors of the  FIG. 2  apparatus that mounts to an actuator mount that is mounted on the heated manifold. 
         FIG. 3  is a front side view of one of the actuators of the  FIG. 1  system mounted to the manifold in conjunction with a second exemplary embodiment of heat convectors according to the invention. 
         FIG. 3A  is a sectional view taken along lines  3 A- 3 A of  FIG. 3 . 
         FIG. 3B  is a sectional view taken along lines  3 B- 3 B of  FIG. 3 . 
         FIG. 3C  is view similar to  FIG. 3B  showing the actuator mounted on a hotrunner or heated manifold and showing a top clamping plate assembled together with the apparatus and the heat convective arm of one of the heat convectors of the apparatus in spring-loaded metal-to-metal contact with the top clamping plate. 
         FIG. 3D  is a rear side view of the  FIG. 3  actuator. 
         FIG. 3E  is a right side view of the  FIG. 3  actuator. 
         FIG. 3F  is a top perspective view of one of the two heat convectors of the  FIG. 3  apparatus that mounts to the valve pin guide bushing. 
         FIG. 3G  is a top perspective view of another one of the two heat convectors of the  FIG. 3  apparatus that mounts to an actuator mount that is mounted on the heated manifold and includes a spring-loaded finger mounted to the arm portion of the convector. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows a pair of actuators  10  mounted to a heated manifold  20  in conjunction with one exemplary embodiment of a pair of heat convectors  30 ,  40  according to the invention. As shown, an actuator  10  having a heat conductive housing  12 , typically metal, is typically mounted on an actuator mount  50  which is in turn typically mounted via conventional mechanisms such as bolts  55 ,  FIGS. 2E, 3E  in compressed metal-to-metal heat conductive contact to and with the heated manifold  20 . The mounting of the actuator housing  12  on the mount  50  is most preferably configured by mounting the housing  12  on an intermediate spacer or standoff  60  that is comprised of a thermally non-conductive material such as titanium, stainless steel, ceramic material or a thermally resistant polymeric material such as polyamide. As shown, the insulator-standoff  60  is bolted at a downstream end to the mount  50  and bolted at an upstream end to a guide bolt  62  that is housed within a sleeve  64  that thermally isolates the bolt  62  from the actuator housing  12 . Thus, the housing  12  is substantially thermally isolated, separated and spaced from direct or indirect metal-to-metal contact with the heated manifold  20  or the mount  50 . 
     With reference to the  FIGS. 2, 2A, 2B, 2C, 2CC ,  2 CCC,  2 D,  2 E,  2 F,  2 G embodiment, the apparatus  5  comprises a heated manifold  20  that receives an injection fluid material  102  injected under high pressure and temperature from an injection molding machine  100  into a fluid distribution channel  22  of the manifold  20 . The heated manifold  20  routes the injection fluid  102  to a downstream fluid delivery channel  200  that extends and delivers the injection fluid material under an injection pressure to a gate  304  of a cavity  302  of a mold  300 . 
     In the  FIGS. 2-2G  embodiment, the actuator housing  12  contains a drive member  14  such as a piston that is interconnected at its downstream end to an upstream end of a valve pin  17  having a drive axis A in an arrangement such that the valve pin  17  is drivable along the drive axis A through a selected stroke length SL between an upstream fully gate open position UO and a downstream gate closed position GC. The actuator housing  12  is mounted on an upstream surface  25  of the heated manifold  20 . A downstream end  16  of the actuator housing  12  is spaced a selectable distance upstream of the upstream surface forming a gap G between the downstream end  16  of the actuator housing  12  and the upstream surface  25  of the heated manifold  20 . 
     As shown in  FIGS. 1-3G  the apparatus  5  includes one or more heat convectors  30 ,  40  each heat convector having a heat conductive leg  36 ,  46  that is disposed within the gap G in heat conductive communication with the heated manifold  20 . Each convector  30 ,  40  has a heat conductive arm  32 ,  42  and arm portion  32   a ,  42   a  that extends distally upstream and radially away R from the gap G and manifold  20  and actuator housing  12  such that heat is conducted from the leg  36 ,  46  to the arm  32 ,  42  upstream and radially away R from the downstream end  16  of the actuator housing  12 . The distal arm portions  32   a ,  42   a  typically extend along an axis or direction P that is generally parallel to the drive axis A of the piston  14  and valve pin  17 . 
     In an alternative embodiment as shown in  FIGS. 2A  and  2 CCC, the convectors  30 ,  40  can be configured and adapted such that the distally extending portion  32   b ,  42   b  of the arm  32 ,  42  extends distally such that it is spaced radially R away from the gap G and manifold  20  and the actuator housing  12 . The distal arm portions  32   b ,  42   b  typically extend along an axis or direction P that is generally perpendicular to the drive axis A of the piston  14  and valve pin  17 . 
     With reference to  FIGS. 1-3G , the heat conductive leg  36 ,  46  of at least one of the heat convectors  30 ,  40  is mounted in metal-to-metal heat conductive communication with the heated manifold  20 . As shown in the Figures, the leg  36  of one of the convectors  30  is mounted in metal-to-metal contact with the guide bushing  90  via force or slip fitting of the bushing head  90  into a complementary aperture  37  provided in leg  36  where the interior circumferential surface  37   a  is in intimate contact with the outside circumferential surface of the head of bushing  90 . The bushing  90  is in turn mounted in metal-to-metal thermally conductive contact with the outer mounting portion  92  of the guide bushing which is in turn mounted in metal-to-metal contact with the heated manifold  20  as shown via slip or force fit insertion of bushing portion  92  into a complementary mounting aperture  23  provided in manifold body  20 . 
     The leg  46  of the other of the convector  40  is mounted in metal-to-metal contact with the mount  50  which is in turn mounted in metal-to-metal contact with the upstream surface  25  of the heated manifold or hotrunner  20 . 
     Legs  36 ,  46  are in heat conductive communication with the manifold  20  by virtue of their mounting or disposition within gap G. Legs  36 ,  46  are also either integral with or in direct metal-to-metal contact with arms  32 ,  42 . Heat that is transmitted to or contained within legs  36 ,  46  is transmitted or convected radially along the length of the legs  36 ,  46  to the arms  32 ,  42  which in turn transmit and dissipate the transmitted heat in the upstream direction. As shown, the legs  36 ,  46  are spatially separated from the bottom end or undersurface  16  of the actuator housing  12 . Legs  36  and  46  are also substantially thermally isolated from the actuator housing  12  except for relatively incidental downstream metal-to-metal contact by legs  46  with thermal insulator standoffs  60  and contact of leg  36  with bushing  90  which is in turn in contact with valve pin  17  which is in turn in contact with piston  14 . Thus, legs  36 ,  46  are isolated from direct metal-to-metal contact with the actuator housing  12  or other actuator components and thermally isolated therefrom serving to maintain the actuator  10  in a relatively cool condition relative to the heated manifold. As shown in  FIGS. 3, 3A , legs  46  are in metal-to-metal thermal or heat conductive contact with the actuator housing  12  by virtue of direct metal-to-metal contact of leg  46  with metal standoffs  60  which in turn are in direct metal-to-metal contact with housing  12 . 
     The heat conductive arms  32 ,  42  of at least one of the heat convectors  30 ,  40  is spaced a distance  15  radially apart R from the actuator housing  12  relative to the drive axis A. Preferably both arms  32 ,  42  are spaced  15  apart from direct metal-to-metal contact with the actuator housing  12 . Such spacing  15  serves to enable the arms  32 ,  42  to transmit heat contained with the arms  32 ,  42  to ambient surrounding air or gas thus thermally isolating the actuator  10  and its components from direct heat or thermal communication with the heated manifold  20 . 
     As shown in  FIGS. 2C, 3C, 3E , an upstream end  33 ,  43  of the heat conductive finger portions  32   a ,  42   a  of arms  32 ,  42  of at least one of the heat convectors  30 ,  40  can be disposed in metal-to-metal heat conductive communication with a relatively cool plate  80  such as a top clamping plate that is mounted in heat conductive isolation from the heated manifold  20 . As shown, the arms  32 ,  42  can be configured to include a finger  32   a ,  42   a  that is slidably mounted on a rod  34 ,  44  that is in turn mounted to a leg  36 ,  46  as shown. A spring  35 ,  45  can be disposed between the fingers  32   a ,  42   a  and their mounting structure  36 ,  46  and the assembly assembled together with cooled plate  80  in an arrangement whereby the spring  35 ,  45  exerts a constant force F on the fingers  32   a ,  42   a  when the spring is compressed to urge the upstream end  33 ,  43  of the fingers  32   a ,  42   a  into compressed metal-to-metal contact with the relatively cool plate  80 . In such a configuration, heat contained in the arms  32 ,  42  is transmitted to the cool plate  80  thus further serving to dissipate heat generated by the heated manifold  20  and to thermally isolate the actuator  10  and its components  12 ,  14  from heat generated by the manifold  20 . 
     The valve pin  17  is slidably received within a complementary guide channel  93  of the bushing  90  for reciprocally driven upstream-downstream movement A along the drive axis A of the valve pin  17 . An actuator mount is mounted in metal-to-metal heat conductive contact with the heated manifold, wherein the leg of at least one of the one or more heat convectors is mounted in metal-to-metal heat conductive contact with the actuator mount. 
     As shown in the alternative embodiment of  FIGS. 3-3G , the convector  30  may comprise a single unitary metal or heat conductive component having a leg portion  36  that is mounted and disposed within the gap G between the manifold  20  and the downstream end  16  of the actuator  10 . 
     Also in an alternative embodiment, the convectors  40  can comprise a leg portion  46  to which is mounted a movable arm portion  42  having a slidable finger  42   a  mounted as shown in  FIGS. 3A, 3D, 3E, 3F  for constant force F upstream urging into metal-to-metal heat conductive contact with plate  80 . Such metal-to-metal contact causes heat contained within the arm  42  to be transmitted to and dissipated within the plate  80  thus serving to thermally isolate and insulate the actuator  10  and its components  12 ,  14  and the like. 
     In an alternative embodiment of the assembled apparatus  5 , one or the other or both of the arm portions  32 ,  42  are not mounted such that they are in physical contact or engagement with the plate  80 . Instead the upstream extension of the arms  32 ,  42  are disposed in contact with only surrounding ambient air which by itself effects dissipation of heat emanating from the manifold  20  that is transmitted to arms  32 ,  42 . 
     The plate  80  is preferably maintained relatively cool relative to the manifold  20  by being mounted and assembled together with the manifold such that the plate  80  is thermally isolated from the manifold either by insulating standoffs between the manifold  20  and the plate  80  or by mounting the plate  80  to the mold without any metal-to-metal or other significant direct or indirect heat conductive contact between the plate  80  and the mold  20 . The plate  80  can be proactively cooled by injection of cooling fluid such as water or antifreeze through cooling channels  82  that can be drilled into the body of the mounting plate (sometimes referred to as a top clamping plate or top clamp plate). 
     In an alternative embodiment as shown in  FIGS. 2A  and  2 CCC, the convectors  30 ,  40  can be configured and adapted such that the distally extending portion  32   b ,  42   b  of the arm  32 ,  42  extends distally spaced away from the manifold  20  and the actuator housing  12  along an axis or direction P that is generally perpendicular to the drive axis A of the piston  14  and valve pin  17 . The arms  32 ,  42  may or may not be in physical contact with a cooler or cooled plate such as top clamping plate  80 . As shown in the  FIG. 2A  embodiments, the arm  32  is not in physical contact with another plate or relatively cool component but it could be so arranged if desired. As shown in FIG.  2 CCC, the arm  32  and finger portion  32   b  in the embodiment where the arm extends along axis P are in physical contact under spring  35  force with the cool plate  80 . 
     In another embodiment, heat conductive pipes  500  can be mounted within the body of the legs  36 ,  46  or arms  32 ,  42  of the heat convectors  30 ,  40  such heat conductive pipes containing heat conductive fluid as disclosed in U.S. Pat. Nos. 4,500,279, 4,389,002, 5,545,028, 5,554,395 and 5,885,628 the disclosures of all of which are incorporated by reference as if fully set forth herein. Such heat conductive pipes once mounted in metal-to-metal contact with a bore or channel drilled into the metal bodies of either a leg  36 ,  46  or arm  32 ,  42  will cause heat to conduct more readily and efficiently from and between the legs  36 ,  46  and the arm portions  32 ,  42  of the convectors or conductors  30 ,  40 . 
     Notches, grooves, recesses and other engravings  600 ,  602  that increase the overall surface area of the legs  36 ,  46  and arms  32 ,  42  can be formed, drilled and engraved into the surfaces and bodies of the legs  36 ,  46  and arms  32 ,  42 . Such engravings  600 ,  602  can increase the thermal conductivity of the convectors  30 ,  40  thus increasing the rate of thermal energy transfer between the legs and the arms as well as to the ambient air or to the plate  80 . 
     A fan  700  that blows or circulate ambient air  702  in a direction into contact with the convectors  30 ,  40  can be included, the moving or circulating air  702  increasing the conductivity of heat between the legs and the arms as well as to the ambient air or to the plate  80 .