Patent Publication Number: US-6665934-B2

Title: Method for making heat dissipation device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation-in-part (CIP) application of my U.S. patent application Ser. No. 09/768,405, filed on Jan. 24, 2001, now abandoned entitled Heat Dissipation Device and whose disclosure is incorporated by reference herein. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to methods for making heat dissipation devices, and more particularly to a method for making a heat dissipation device which provides great heat removal capability. 
     2. Related Art 
     Electronic devices such as central processing units (CPUs) generate a lot of heat during normal operation. This can deteriorate their operational stability and damage associated electronic devices. Thus the heat must be removed quickly to ensure normal operation. A heat dissipation device is often attached to a top surface of a CPU, to remove heat therefrom. 
     A conventional heat dissipation device is formed by extrusion, which significantly limits the height of its formed fins. Furthermore, to meet increasing demands for dissipation of ever-increasing amounts of heat, larger and larger heat dissipation devices are being manufactured. This results in excessively heavy heat dissipation devices, and high costs for manufacturers. 
     To resolve the above-mentioned problems, another kind of heat dissipation device has been developed. The fins of such device are folded from a metal sheet. A chassis in thermal contact with a CPU supports the fins. The device has a large heat dissipation surface area. However, because the fins are folded from a metal sheet, a cooling fan cannot be easily and securely attached to the fins. The device generally removes heat without the benefit of a fan. Furthermore, the chassis of the heat dissipation device is generally a thin metal plate. This limits heat conduction, thereby reducing the efficiency of heat transfer. Oftentimes, the device cannot satisfactorily remove heat from the CPU. 
     In other conventional heat dissipation devices, a metal block is attached to a bottom of a chassis of the device. This increases a thickness of the chassis engaging with the heat-generating electronic device, and thereby attains higher heat conduction. However, the extra materials required increase manufacturing costs. Furthermore, gaps exist between the metal block and the chassis, thereby retarding heat transfer. Oftentimes, such device cannot attain the required level of heat conduction. 
     A method for making an improved heat dissipation device which overcomes the above-mentioned problems is strongly desired. 
     SUMMARY OF THE INVENTION 
     Accordingly, an object of the present invention is to provide a method for making a heat dissipation device which has great heat removal capability. 
     Another object of the present invention is to provide a simple, efficient and economical method for making a heat dissipation device. 
     To achieve the above-mentioned objects, a method for making a heat dissipation device in accordance with the present invention comprises the steps of: providing a metal plate and a fin member, bending the metal plate to form a body, and attaching the fin member to the body. The metal plate comprises a central portion and a pair of end portions. The central portion is thicker than the end portions. The body comprises a chassis originating from the central portion of the metal plate, and a pair of side walls originating from the end portions of the metal plate. The fin member is attached to the chassis between the side walls. 
    
    
     Other objects, advantages and novel features of the present invention will be drawn from the following detailed embodiments of the present invention with attached drawings, in which: 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side view of a metal plate for making a body of a heat dissipation device in accordance with a preferred embodiment of the method of the present invention; 
     FIG. 2 is an exploded view of a heat dissipation device made in accordance with the preferred embodiment of the method of the present invention; 
     FIG. 3 is an assembled view of FIG. 2; and 
     FIG. 4 is an assembled view of another heat dissipation device made in accordance with an alternative embodiment of the method of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     FIGS. 1-3 show various aspects of making of a heat dissipation device  3  in accordance with a preferred embodiment of the method of the present invention. The heat dissipation device  3  comprises a fin member  1  and a body  2 ′ made from a metal plate  2 . The body  2 ′ supports the fin member  1  thereon. The fin member  1  is concertinaed from a single sheet by conventional means, to provide maximum surface area for heat dissipation. 
     Referring to FIG. 1, the metal plate  2  has a central portion  22  and a pair of end portions  24  extending from opposite sides of the central portion  22  respectively. The central portion  22  and end portions  24  have coplanar top surfaces. Bottom surfaces of the end portions  24  are coplanar. A bottom surface of the central portion  22  is lower than the bottom surfaces of the end portions  24 . The central portion  22  is thereby thicker than the end portions  24 . 
     The end portions  24  of the metal plate  2  are bent upwardly from the opposite sides of the central portion  22  respectively, thereby forming the body  2 ′. The body  2 ′ comprises a chassis  22 ′ originating from the central portion  22  of the metal plate  2 , and a pair of parallel side walls  24 ′ originating from the end portions  24  of the metal plate  2 . The side walls  24 ′ are perpendicular to the chassis  22 ′, and the body  2 ′ has a substantially U-shaped configuration. The chassis  22 ′ is for thermal contact with a heat-generating electronic device (not shown). The chassis  22 ′ is thicker than either side wall  24 ′, for enhancing heat transfer from the electronic device to the heat dissipation device  3 . 
     Referring to FIG. 3, in assembly, the fin member  1  is attached to a top surface of the chassis  22 ′ between the side walls  24 ′. The heat dissipation device  3  has a large heat dissipation surface area and a thick chassis  22 , for enhancing heat removal. 
     FIG. 4 shows a heat dissipation device  3 ′ made in accordance with an alternative embodiment of the method of the present invention. The heat dissipation device  3 ′ is similar to the heat dissipation device  3  disclosed in FIGS. 2 and 3. However, a body  2 ″ of the heat dissipation device  3 ′ further comprises a pair of horizontal flanges  26 ′. The flanges  26 ′ are formed at respective diagonally opposite upper corners of the side walls  24 ″, and extend perpendicularly inwardly from top edges of the side walls  24 ″ respectively. Each flange  26 ′ defines a through hole  28 ′ therein for engagement with a fan (not shown) giving enhanced cooling air flow. When the heat dissipation device  3 ′ is assembled, the flanges  26 ′ are disposed above the fin member  1 . For brevity, a detailed description of the heat dissipation device  3 ′ is omitted herefrom. Instead, reference is made to the detailed description of the heat dissipation device  3 . 
     Further alternative embodiments of the present invention include replacing the fin member  1  with a plurality of parallel metal plates. Such plates perform the same function as the fin member  1 . 
     It is understood that the invention may be embodied in other forms without departing from the spirit thereof. Thus, the present examples and embodiments are to be considered in all respects as illustrative and not restrictive, and the invention is not to be limited to the details given herein.