Patent Publication Number: US-3880491-A

Title: Male plug assembly incorporating power supply

Description:
United States Patent n Ferro et al.  
 [ Apr. 29, 1975 MALE PLUG ASSEMBLY INCORPORATING POWER SUPPLY [75] Inventors: Armand P. Ferro: Nancy D. Fitzroy.  
 both of Schenectady. NY.  
 [73] Assignee: General Electric Company.  
 Schenectady. NY.  
  22 Filed: May 30. 1974 2| Appl.No.:474,669  
 (52] US. Cl. 339/ll2 R; 339/63 Rzl76 R [St] Int. Cl l-l0lr 13/00 [58] Field of Search 339/1 [2 R. 42. 62. 63 R. 339/63 M. [76 R. [95 R. 195 M. 196 R. I96 M [56] References Cited UNITED STATES PATENTS 2.9l5.732 l2/l959 Pifcr 339/62 X 5/l970 Dcgactano 339/42 l2/l97l Eckcrt 339/42 X Primary E.\&#39;uminvr-Roy Lake Assistant E.\&#39;uminerDeWalden W. Jones Attorney, Agent. or Firm-Jack E. Haken; Joseph T. Cohen; Jerome C. Squillaro [57] ABSTRACT A power supply is incorporated in a male plug assembly at one end ofa line cord. The male plug assembly is provided with means for preventing said assembly from abutting against a wall when said male plug is received in a female receptacle in said wall The aforesaid means maintains an air space between the wall and the assembly thereby enabling convection air currents to dissipate the heat produced by the power supply.  
 8 Claims. 5 Drawing Figures MALE PLUG ASSEMBLY INCORPORATING POWER SUPPLY BACKGROUND OF THE INVENTION- The subject invention pertains, in general, to power supplies which are incorporated at one end of a line cord together with a male plug which is adapted to be received in a wall-mounted female receptacle; and, in particular. to an assembly including a male plug, a power supply and means for preventing said assembly from abutting the wall which includes the female receptacle so as to enable the passage of convection air currents between the wall and the aforesaid assembly and thereby improve heat transfer from the assembly.  
  There are many applications where it is advantageous to incorporate a small volume, light-weight power supply at one end of a line cord together with a male plug which is adapted to be received in a wall-mounted female receptacle. For example, such a power supply may be incorporated in a conventional two, or three, conductor line cord at one end of the line cord and assembled together with a male plug which is adapted for connection with a wall receptacle which supplies a single phase. 60 hertz source of I volts. The power supply unit converts the supplied phase. frequency and voltage to suit the appliance, or appliances. which are intended to be connected to the end of the line cord. The described assembly is often called a line cord power supply. The power supply is a small, compact, lightweight unit which is integral with the line cord and is supported by the plug. The power supply includes heat dissipating circuit elements such as semiconductor devices, resistors, etc. Ordinarily, the male plug is inserted into a wall-mounted female receptacle and the entire assembly, including the power supply, abuts against the wall so that no air space is left between the wall and the aforesaid assembly. As a result, a substantial surface area of the aforesaid assembly is not available for transferring the heat produced by the heat dissipating elements of the power supply.  
 SUMMARY OF THE INVENTION One object of the invention is to provide a line cord power supply assembly having improved heat transfer capabilities.  
  The aforementioned object, among others, is realized in accordance with one embodiment of the invention by the provision of a line cord power supply comprising: a body of dielectric material; a power supply enclosed in said body; a line cord electrically connected with said power supply and protruding from said body; at least two elongated blades electrically connected with said power supply and protruding from said body, said blades being adapted for being received in female receptacles for establishing a voltage between said blades; and, means on said body for maintaining an air space between said body and said female receptacles when said blades are received in said female receptacles.  
  In accordance with one feature of the invention, the aforesaid means for maintaining the air space is comprised of a plurality of fin members which, in effect, increase the available cooling surface area of the dielectric body and also provide a plurality of separate passages for the flow of convection air currents for the cooling of said dielectric body.  
  In accordance with another feature of the invention, the aforesaid fin members also provide bearing surfaces so as to limit movement of the elongated blades in the female receptacles when force is applied to the dielectric body.  
  Other objects, as well as other features and advantages of the invention, appear hereinafter whereat two exemplary embodiments of the invention are disclosed for the purpose of illustrating the invention; said disclosures including the accompanying drawing figures, the content of which is hereinafter described.  
 DRAWINGS FIG. I is a block diagram showing the various electrical components of which the subject line cord power supply is comprised.  
  FIG. 2 is a side elevation view showing a line cord power supply and male plug assembly in accordance with a first embodiment of the invention.  
  FIG. 3 is a plane view of the assembly of FIG. 2 taken along the line 3-3 of FIG. 2.  
  FIG. 4 is a side elevation view showing another line cord power supply and male plug assembly in accordance with a second embodiment of the invention.  
  FIG. 5 is a plane view of the assembly of FIG. 4, taken along the line 55&#39; in FIG. 4.  
 DETAILED DESCRIPTION In the block diagram shown in FIG. I, the enclosure within the dotted lines [0 represents a body of dielectric material, such as, for example, synthetic rubber or plastic. Within the body 10 there is embedded a line cord power supply which includes: an EMI filter I2; a first rectifier 14&#39;, an inverter 16; a step down transformer I8; another rectifier 20; another filter 22. A pair of electrically-conductive blades 24, 24 is electrically connected to the input of the EMI filter I2, and, as shown in FIG. I, protrude from the body [0. Also, a two-conductor line cord 26 is electrically connected to the output of the filter 22 and. as shown in FIG. I, protrudes from the body 10.  
  Although two blades 24, 24 are shown and although the line cord 26 is shown as having two conductors, it is to be understood that the assembly may include more than two blades and the line cord may include more than two conductors.  
  The power supply comprising the components 12....22, within the body 10, includes such elements, or devices, as capacitors, resistors, semiconductor diodes, transistors, ferrite core members, etc. These elements, or devices, produce heat, to a greater or lesser degree, when electrically energized. It is important that the heat so produced be dissipated from these elements, or devices, in order to avoid damage to the power supply, among other things.  
  In a first specific embodiment of the invention, illustrated at FIGS. 2 and 3, the various components 12....22 of the line cord power supply are embedded in a molded body 10A of dielectric material. For example, the body 10A may be molded from synthetic rubber or a suitable plastic. Protruding from the body 10A is a pair of blades 24, 24. The blades 24 are electrically connected with an EMI filter I2 (not shown in FIGS. 2 and 3) embedded in the body 10A. The molded body 10A includes a front surface 10B and a rear surface 10C, as shown in FIGS. 2 and 3. Integral with and extending from the surface 108 for a distance of about half the length of the blades 24, 24 are a pair of elongated members IOD of dielectric material. The elongated members IOD coaxially encompass elongated portions of the blades 24 therewithin. As shown at FIGS. 2 and 3, the end of each elongated member 10D is provided with a wide flange portion IOE. Also integral with and extending from the surface IOB, as shown in FIGS. 2 and 3, are a plurality of fin members 10F. As shown, the protruding fin members 10F are spaced apart from each other along the surface 10B of the body IOA so that an air space exists between adjacent fin members IOF. Also, as indicated at FIG. 3, air spaces exist between the adjacent elongated members 10]) and fin members IOF. The aforementioned air spaces allow convection air currents to pass, among other places, over the surface [08 of the body 10A. As a result, additional cooling of the body WA and the components 12....22 embedded therein is enabled. The advantages of the fins 10F and elongated members 10D can be better appreciated by reference to FIG. 2. As shown at FIG. 2, the blades 24 of the assembly are illustrated as being received in suitable female receptacles provided in a wall 28. As indicated, the wall 28 includes a surface 28A. With the blades 24 received in the fe male receptacles in the wall 28, the flanges 10E of the elongated members 10D abut the wall surface 28A. Thus, the surface IOB of the body 10A is separated by a distance L from the wall surface 28A. Being separated by the distance L convection air currents can pass, among other places, over the surface 108 of the body IOA&#39;, i.e., the convection air currents pass through the air spaces provided between the fin members 10F and between the elongated members 100 and fin members 10F. With the construction shown in FIGS. 2 and 3, heat generated by the embedded components, I2...22, within the body IDA may be dissipated from all of the exterior surfaces of the body [A. In prior art constructions, the front surface (i.e., the surface 108) would abut the wall surface 28A such that no spacing (such as the distance L) would exist. Consequently, the whole surface IOB would be ineffective as a heat dissipating surface. Advantageously, the fin members 10F, as indicated at FIG. 2, are almost the same height as the height of the front surface 108. As a consequence, if the body [GA is twisted while the blades 24 are in the receptacles in the wall 28, the end portions 100 of the fin members 10F will come into contact with the wall surface 28A and prevent the further twisting of the body 10A. Therefore, as indicated at FIG. 2, the upper and lower end portions 100 serve as bearing surfaces in the event that the body 10A should be twisted clockwise or counterclockwise.  
  A second specific embodiment of the invention is illustrated at FIGS, 4 and 5. The embodiment illustrated at FIGS. 4 and is the same as the embodiment shown at FIGS. 2 and 3, except that fin members F are not employed. Thus, like reference numbers are used in FIGS. 4 and 5 to identify like elements and parts shown in the first embodiment illustrated at FIGS. 2 and 3. As indicated at FIGS. 4 and 5, when the blades 24 of the body 10A are received in a suitable female receptacle in the wall 28, a distance L separates the surface 100 of the body 10C from the wall surface 28A. Thus, convection air currents may pass between the surfaces 103 and wall surface 28A. The single flange 10B is enlarged, as compared with the embodiment shown in &#34;FIGS. 2 and 3. The single flange 10E bridges both members 10D, as shown in FIG. 5. The single flange [0E provides a better bearing surface against wall surface 28A.  
  While specific embodiments of the invention have been illustrated and described in some detail to give examples of the invention, it is to be understood that the invention may be otherwise embodied without departing from the spirit and scope of the invention which is hereinafter defined in the claims.  
 What is claimed is:  
  I. In combination: a power supply, comprising means for converting an input voltage to an output voltage having a different phase, frequency or voltage therefrom, said power supply also including at least two generally parallel spaced-apart elongated blades adapted for being at least partially received in a wall-mounted female receptacle which establishes said input voltage between said blades for energizing said power supply and a line cord having at least two conductors between which said output voltage from said power supply is established&#39;, a body of dielectric material within which said power supply including said converting means is enclosed, said blades protruding from a surface of said body and said line cord protruding from said body at a location remote from said surface; and, dielectric means extending from said surface of said body in the same general direction as said blades and enclosing part of the length of each blade so that an exposed length of each blade extends beyond said dielectric means, said exposed length of the blades being of sufficient length for receipt thereof in said female receptacle, said dielectric means spacing said surface of said body from the wall-mounted receptacle to enable convention air currents to dissipate heat from said body.  
  2. The combination set forth in claim 1 wherein said dielectric means includes at least one rigid projecting flange extending from said means where said means terminates and the exposed lengths of the blades begin and lying in a plane parallel to said body surface so that said flange serves as a bearing surface in contact with the wall-mounted receptacle when said blades are received in said receptacle.  
  3. In combination: a power supply comprising heat producing elements and including at least two generally parallel spaced-apart elongated blades adapted for being at least partially received in a wall-mounted female receptacle which establishes an input voltage between said blades for energizing said power supply, said power supply also including a line cord having at least two conductors between which an output voltage from said power supply is established; a body of dielectric material within which said power supply including said heat producing elements are enclosed, said blades protruding from the surface of said body and said line cord protruding from said body at a location remote from said surface; and, dielectric means extending from said surface of said body in the same general direction as said blades and enclosing part of the length of each blade so that an exposed length of each blade extends beyond said dielectric means, said exposed lengths of the blades being of sufficient length for receipt thereof in said female receptacle as said surface of said body is maintained spaced from the wall-mounted receptacle by said dielectric means to enable convection air currents to cool the surface of said body, said dielectric means including at least one rigid, projecting flange where said means terminate and the exposed lengths of said blades begin so that said flange serves as a bearing surface in contact with the wall-mounted receptacle when said blades are received in said receptacle; a plurality of parallel fin members extending from said surface of said body coextensive with said dielectric means and terminating at distances from said surface of said body short of said flange on said dielectric means, said parallel fin members including between adjacent fin members air spaces for the passage of convection air currents for cooling said surface of said body as well as the surfaces of said fin members.  
  4. The combination set forth in claim 3 wherein said fin members include bearing surfaces at extremities thereof which come into contact with the wall in which said female receptacle is mounted as said body is twisted and said blades in said female receptacle is rotationally moved.  
  5. The combination set forth in claim 1 wherein said dielectric means is integral with said body of dielectric material.  
  6. The combination set forth in claim 5 wherein said dielectric means is bifurcated so that portions of each blade are separately enclosed to said means and a space for convection air currents is provided between the enclosed blade portions.  
  7. In combination: a power supply comprising heat producing elements and including at least two generally parallel spaced-apart elongated blades adapted for being at least partially received in a wall-mounted female receptacle which establishes an input voltage between said blades for energizing said power supply, said power supply also including a line cord having at least two conductors between which an output voltage from said power supply is established; a body of dielectric material within which said power supply including said heat producing elements are enclosed, said blades pro truding from a surface of said body and said line cord protruding from said body at a location remote from said surface; and, bifurcated dielectric means integral with said body extending from said surface of said body in the same general direction as said blade and enclosing part of the length of each blade so that an exposed length of each blade extends beyond said dielectric means and so that portions of each blade are separately enclosed to said means and a space for convection air currents is provided between the enclosed blade portions, said exposed length of the blades being of sufficient length for receipt thereof in a female receptacle as said surface of said body is maintained spaced from the wall&#39;mounted receptacle by said dielectric means to enable convection air currents to cool said surface of said body; a plurality of parallel fin members extending from said surface of said body coextensive with said bifurcated dielectric means and terminating at distances from said surface of said dielectric body short of where the exposed blades begin, said fin members being integral with said dielectric body and including between adjacent fin members air spaces for convection air currents.  
  8. In combination: at least one heat-producing electrical circuit element, comprising a resistor, semconductor device, capacitor. semiconductor diode, transistor, or ferrite core member; at least two generally parallel spaced-apart elongated blades electrically connected with said at least one circuit element, said elongated blades being adapted for being received in a female receptacle mounted in the surface of a wall, said female receptacle being adapted for establishing an input voltage between said elongated blades and energizing at least one circuit element; a body of dielectric material within which said circuit element is enclosed, said blades protruding from the surface of said body; and, means on said body for separating said surface of said body and said body from said wall when said blades are received in said female receptacle so that convection air currents may cool substantially the en tire body.  
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