Patent Publication Number: US-2007114194-A1

Title: Fastening mechanism for electronic devices

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to technologies for fastening circuit units of electronic devices, and more particularly, to a fastening mechanism for fastening a circuit board to an electronic device.  
      2. Description of Related Art  
      A wide range of PCs and servers have been designed to meet industrial requirements. It is desirable and advantageous to use a standard machine cabinet that can accommodate different models of computer motherboards so that when a motherboard is replaced the cabinet can continue to be used.  
      The base panel in a conventional server/PC cabinet typically has a plurality of screw holes prepared on its front, back and bottom surfaces for installing therein a variety of motherboards of different models. Similarly, the motherboards are formed with a plurality of corresponding holes for receiving screws serving as fastening mechanisms to thereby fasten motherboards to server/PC cabinets.  
      While the screw/hole method can fasten different models of motherboards to servers/PC cabinets, when fastening a relatively large motherboard, it is often cumbersome to find the matching holes and this, in turn, can result in mal-positioning.  
      Further, in using screws as a fastening means to fasten a motherboard to a machine cabinet, it is necessary to prepare in advance copper pillars or similar elevated structures to space apart the motherboard and the base panel of the cabinet to prevent electrical short circuit from occurring. Larger motherboards necessitate more screw holes for fastening and also more elevated structures to prevent short circuits, adversely wasting time and cost for installing motherboards.  
      Such problems related to drilling holes for fastening are not limited to screw fasteners but are also present with regard to fastening mechanisms of many sorts, such as screws or rivets.  
      Similar problems also apply to portable electronic devices such as notebook computers (NB), and personal digital assistants (PDA) using such a fastening means as screw or rivets. Therefore, there exists a need to develop a fastening mechanism that enables users to rapidly and conveniently secure a motherboard to an electronic device.  
     SUMMARY OF THE INVENTION  
      The present invention aims to eliminate the aforementioned drawbacks, and, as such, a primary objective of the present invention is to provide a fastening mechanism that enables a user to conveniently and rapidly install motherboards of different models and sizes in an electronic device.  
      Another objective of the present invention is to provide a fastening mechanism that can be applied to a variety of circuit boards for electronic devices.  
      Another objective of the present invention is to provide a fastening mechanism that can simplify the steps of installing a circuit board into an electronic device and reduce costs as a result.  
      In order to achieve the above and other objectives, the present invention provides a fastening mechanism for fastening a circuit board to an electronic device, the fastening mechanism being comprised of: a carrier for carrying the circuit board; a fastening member having a first retaining portion that is connected to said carrier for coupling to at least one side of said circuit board; a guiding member disposed on said carrier that extends away from the direction of said fastening member; an active member disposed on said guiding member that consists of a second retaining portion for coupling to an opposite side of said circuit board, and a sheathing member for correspondingly coupling with said guiding member, thereby allowing said active member to move along said guiding member by means of the sheathing member to jointly fasten a variety of circuit boards of different sizes with said fastening member.  
      In addition, the fastening member of the present invention further comprises an operational portion for correspondingly operating with said sheathing member, which is adapted to control the tightness of said sheathing member on the guiding member so as to adjust the position of the active member on the guiding member.  
      In fastening a circuit board to an electronic device, firstly one side of the circuit board is connected to a first retaining portion of said fasting member, then the position of the active member on the guiding member is adjusted such that said first retaining member and said second retaining member are tightly fastened to the circuit board, and further an elevation between said circuit board and said carrier is formed concurrently to prevent electric short circuits from happening.  
      Compared to the complex methods in which screws/rivets are used to fasten a circuit board to an electronic device, the circuit board fastening mechanism proposed by the present invention is designed to eliminate the need of using a fastening tool and thus is easy and quick to operate. Further, when attempting to locate the corresponding screw holes in prior methods, it often takes longer and is difficult to install, especially for circuit boards in larger sizes (such as servers and PCs), and in the case that screw holes are not fastened accurately with precision, there is a tendency to generate inner stress in the circuit board that can result in structural damage due to the mal-positioning or misplacement of screw. On the contrary, the fastening mechanism of the present invention engages and fastens the side edges of a circuit board without the drawback of potentially applying inappropriate or unbalanced forces to the circuit board and thus has the lasting benefit of helping to protect the circuit board from stress after installation.  
      Summarizing the above, the fastening mechanism according to the invention not only can fasten a circuit board to an electronic device securely, but also is convenient and quick to operate. Accordingly, the present invention offers advantages over the prior art techniques due to its easy-positioning and installation without the potential for damage to circuit boards due to inappropriate forces being exerted by misused prior-art fasteners. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
      The fastening mechanism of the present invention can be fully understood by reading the following detailed description of the preferred embodiments, with reference made to the accompanying drawings, wherein:  
       FIG. 1  is a perspective view showing a first preferred embodiment of the fastening mechanism according to the present invention;  
       FIGS. 2A and 2B  are, respectively, a perspective view and a corresponding cross-sectional view showing the fastening member of the first preferred embodiment of the fastening mechanism according to the present invention;  
       FIG. 3  is a perspective view showing a second preferred embodiment of the fastening mechanism according to the present invention;  
       FIG. 4A  is a perspective view showing the fastening member of the second preferred embodiment of the fastening mechanism according to the present invention;  
       FIG. 4B  is a cross-sectional view of the fastening member of the second preferred embodiment of the fastening mechanism according to the present invention showing an auxiliary supporting structure;  
       FIG. 4C  is an oblique-angle view of the fastening member of the second preferred embodiment of the fastening mechanism according to the present invention showing an auxiliary supporting structure;  
       FIG. 5A  is an oblique-angle view showing the connection of an active member and a guiding member of the fastening mechanism according to the present invention;  
       FIG. 5B  is a side view of the active member of the fastening mechanism showing a sheathing structure thereof according to the present invention;  
       FIG. 6A  is a perspective view showing the active member of the fastening mechanism according to the present invention; and  
       FIG. 6B  is a cross-sectional view of the active member of the fastening mechanism showing an auxiliary supporting structure, according to the present invention. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENT  
      The present invention is described in the following with specific embodiments, so that one skilled in the pertinent art can easily understand other advantages and effects of the present invention. The present invention may also be implemented and applied according o other embodiments, and the details may be modified based on different views and applications without departing from the spirit of the invention. Also, note that all of the ensuing drawings in this specification are simplified schematic diagrams to show only those parts related to the invention; the parts illustrated are not drawn and depicted according to actual scale, size, or number, the details of which are arbitrary/willful design choices in the actual implementation of the invention.  
       FIGS. 1A  depicts a first preferred embodiment of the fastening mechanism according to the present invention, the fastening mechanism being configured in a machine cabinet of an electronic device for fastening a circuit board to the electronic device. Said electronic device cabinet  1  can be the machine cabinet of a PC, a server, a portable electronic device, or any device accommodating boards that can be interchanged.  
      The fastening mechanism according to the present invention is at least comprised of: a carrier  10  adapted to carry a circuit board  5 , said circuit board  5  having corresponding sides  50 ,  51 ; a fastening member  2  fixedly connected to said carrier  10  having a first retaining portion such as a clipping groove  21  a for coupling the side  50  of said circuit board; at least one guiding member  3  disposed on said carrier  10  which extends away from the direction of said fastening member  2 ; an active member  4  disposed on said guiding member  3 , said active member  4  being constituted to include a second retaining member  41  which is connected to an opposite side  51  of said circuit board  5  and a sheathing member  42  for coupling with said guiding member  3 , thereby allowing said active member  4  to move along said guiding member  3  by means of the sheathing member  42  so as to jointly fasten circuit boards in a variety of different sizes with said fastening member  2 .  
      Note that parallel elements that are used in the present invention share identical structural theory and only differ in the direction of engaging said circuit board  5 . Thus for clarify and brevity, only the detailed structure of one element is described herein to enable persons skilled in the pertinent art to infer without the difficulty from the described element.  
      Referring to  FIGS. 2A and 2B , in which  FIG. 2A  illustrates the structure of the fastening member  2 , and  FIG. 2B  is a cross-sectional view showing the engagement of the fastening member  2  with the circuit board  5 , said fastening member  2  is made of an insulating material and rigidly connected to said carrier  10 , so that one side  50  of said circuit board  5  is propped up to couple with said clipping groove  21   a  to form an elevation L to space apart the circuit board  5  from said carrier  10 . Note that said fastening member  2  is not intended to be limited to holding a rectangular circuit board.  
       FIG. 3  illustrates a second preferred embodiment of the fastening mechanism according to the present invention. As shown, the first retaining portion of said fastening member  2  is an opening  21   b  for receiving a corner of said circuit board  5  so as to stably and securely hold said circuit board  5  therein.  
      Referring-to  FIGS. 4A  to  4 C,  FIG. 4A  is an oblique-angle view showing the structure of the fastening member  2  engaging with said circuit board  5 , and  FIGS. 4B and 4C  are, respectively, a cross-sectional view and an oblique-angle view showing an auxiliary supporting structure of the fastening member  2 . As shown in  FIG. 4A , the fastening member  2 , which is made of an insulating material, is constituted to have an opening  21   b  so as to couple with a corner of the circuit board  5 , wherein said circuit board  5  is spaced apart from said carrier  10  by an elevation L due to the coupling with said opening  21   b.    
      Referring to  FIGS. 4B and 4C , said first retaining portion further includes a groove  210  disposed at the opening  21   b  for embedding said circuit board  5  and supporting said circuit board  5  in an opposite direction of the carrier. Said groove  210  may be formed on one side of the opening  21   b  for embedding said circuit board  5 , or on the both sides of the opening  21   b  for embedding the corner flanges of said circuit board  5  depending on the design choice.  
      Referring to  FIGS. 5A and 5B ,  FIG. 5A  is an oblique-angle view showing the coupling of an active member  4  and a guiding member  3 , and  FIG. 5B  is a side view of the active member  4 , wherein the active member  4  is connected to said guiding member  3  by means of a sheathing portion  42 , said guiding member  3  being a sliding track and said sheathing portion  42  is an adjustable opening. Said active member  4  further includes an operational portion  43  to correspondingly actuate said opening by using the torque spring effect to adjust the coupling tightness of said opening on the sliding track, allowing said active member  4  to slide freely on said guiding member  3 .  
      Referring to  FIG. 6A and 6B ,  FIG. 6A  is an oblique-angle view showing the coupling of the active member  4  with the circuit board  5 , and  FIG. 6B  is a cross-sectional view showing an auxiliary supporting structure of said active member  4 . As shown in  FIG. 6A , said fastening member  4  is made of an insulating material and the second retaining portion  41  thereof is located at the opening  41   b  of the active member  4  to couple with an edge of said circuit board  5 . By coupling with the first retaining portion of the fastening member and the second retaining portion  41  of said active member  4 , said circuit board  5  is spaced apart from said carrier  10  by an elevation L.  
      As shown in  FIG. 6B , the opening  41   b  of the second retaining portion  41  may further be constituted to form a groove  410  therein for embedding said circuit board  5  and supporting said circuit board  5  in an opposite direction of the carrier, wherein said groove  410  can be formed on one side of the opening  41   b  for embedding said circuit board  5 , or on the both sides of the opening  41   b  for embedding the corner flanges of said circuit board  5  depending on the design choice.  
      Compared to the complex methods in which screws/rivets are used to fasten a circuit board to an electronic device, the circuit board fastening mechanism proposed by the present invention is designed to eliminate the need of using a fastening tool by coupling the edges and flanges of a circuit board, enabling easy and rapid installation. Further, the fastening mechanism is made of an insulating material as opposed to those of conductive metallic material as used in the prior art, preventing electric short circuits from occurring.  
      In summary, prior art circuit units were structured such that a plurality of independent holes had to be prepared on surfaces of a machine cabinet to which other components attached. As a result, productivity was low and the production cost was increased. These holes must be prepared by machining as a secondary process and the preparation of these holes involves a number of extra steps, and, as mentioned before, the larger the circuit board, the more holes that are required as well as the elevation structures for preventing short circuits, such a system adversely increasing time and cost. On the other hand, the fastening mechanism according to the present invention not only can fasten a circuit board to an electronic device securely without using tools, but also is simple and quick to operate. Accordingly, the present invention offers advantages over the prior art techniques for its easy-positioning and installation without causing damage to circuit boards due to inappropriate forces being exerted.  
      The aforementioned are only exemplary preferred embodiments of the present invention. The scope of the claims as stated below should be accorded the broadest interpretation so as to encompass various modifications and similar arrangements made to the herein described invention that fall within the spirit of the basic principles and technology of the present invention.