Abstract:
The present invention relates to packages for peripheral devices such as memory media and input/output (I/O) devices. The package comprises a top cover and a bottom cover secured to a frame. The covers are secured to the frame through a locking mechanism wherein hooks on the covers lock with and conform around latches on the frame. Methods of making and assembling the package are also disclosed.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to packages for peripheral devices such as memory media and input/output (I/O) devices. Typically the package holds a printed circuit board (PCB), where the device conforms to standards set by Personal Computer Memory Card International Association (PCMCIA), Japan Electronic Industry Development Association (JEIDA), International Organization for Standardization (ISO), etc. for peripheral devices.  
           [0003]    2. Description of Prior Art  
           [0004]    The current trend in the computing hardware, telecommunications and electronics industries is to miniaturize components and devices and to place as many of the components and devices next to each other so as to provide quality technical performance in a small package. In order to expand a portable, laptop, or any other type of computer&#39;s capacity and functioning capability, manufacturers have devised “plug-in” peripheral cards in the form of printed circuit boards (PCB&#39;s) contained within an exterior package. These devices are termed “PCMCIA style peripheral devices”. Such packages have typically been formed from steel with plastic molded frames. However, such packages do not provide a rigid, robust, and precise datum surface upon which a precision assembly may be manufactured.  
           [0005]    Certain Personal Computer (PC) card, compact flash or small form factor cards are needed that provide a rigid, accurate structure support for applications such as mini disk drives. The current steel covers with plastic molded frames do not provide enough torsional resistance to external forces, for instance, for such precision PC card applications, liquid crystal diode (LCD) displays, hinges, security devices, personal digital assistants (PDA), digitization of analog information scanners, internet connections, and other wireless communication applications. Also, traditional molding methods result in too much shrinkage, thus forming surfaces not having accurate dimensions. Therefore, it is desired to provide the manufacture of components such as PC cards using materials and compounds that may provide an accurate datum plane due to accurately manufactured parts that are stiff and strong.  
           [0006]    Prior art PCMCIA cards typically have two sheet metal covers that are joined together by a plastic frame molded around each cover, as disclosed in U.S. Pat. Nos. 5,397,857 and 5,475,919, the disclosures of which are hereby incorporated by reference. The plastic frames are welded together using ultrasonic welding or resistance welding. The electrically conductive, sheet metal of the top and bottom covers provide a shielding effect against the transmission of electromagnetic radiation through the top and bottom covers. A drawback of the this system is that the ultrasonic welding process may result in damage to components on the PCB due to ultrasonic energy transfer to the PCB if not properly designed.  
           [0007]    Other prior art packages employ a “snap together” approach such as U.S. Pat. Nos. 5,505,628; 5,510,959; and 5,574,628, the disclosures of which are also hereby incorporated by reference. This approach employs the use of covers that have mechanical overlaps which attach one cover to the other cover at discrete intervals along the side edge of the package. The mechanical overlaps electrically ground the two covers to each other. The mechanical overlaps traverse or cross over the side edge of the package, as such, only intermittent shielding is provided, which not acceptable. Such solutions, however, add to the size, complexity, material cost, and labor cost of the package. Further, the “snap together” approach does not offer a tight lock that provides rigidity and overall strength.  
           [0008]    Therefore, there is a need for a simple to manufacture, assemble package that has high strength and minimizes deleterious effects on the PCB.  
         SUMMARY OF THE INVENTION  
         [0009]    An object of the present invention is to provide a package for peripheral devices. The package comprises a top cover and a bottom cover secured to a frame. The covers are secured to the frame through a locking mechanism wherein hooks on the covers lock with and conform around latches on the frame. The covers and the frame, when assembled, are capable of encapsulating a PCB and affixing it in proper position.  
           [0010]    A further object of the present invention is to provide methods of making a package for peripheral devices. The package has a locking mechanism that is held together with friction that is stronger than prior art packages and requires no welding.  
           [0011]    The advantages of the present invention are numerous. Because the molding of the frame and the stamping of the covers are independent steps, the manufacturing time are reduced, thereby lowering manufacturing cost. The process of stamping and molding are well known and well define; therefore, changes to the extended design requires only minimal additional tooling. The multiple locks and tight tolerances result in high rigidity and enclosure strength which are stronger, faster to assemble and more reliable than bonded or “snap together packages.” The mechanical locks do not require ultrasonic welding that can damage components on the PCB. And lastly, the assembly process can be fully automated because of the simplicity and well defined nature of the process. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]    The foregoing background and summary, as well as the following detailed description of the drawings, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there is shown in the drawings embodiments which are presently preferred. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown. In the drawings:  
         [0013]    [0013]FIG. 1 shows the top view of the bottom cover.  
         [0014]    [0014]FIG. 2 shows the side view of the bottom cover.  
         [0015]    [0015]FIG. 3 shows the cross-section A-A of the bottom cover.  
         [0016]    [0016]FIG. 4 shows the cross-section B-B of the bottom cover.  
         [0017]    [0017]FIG. 5 shows the back view of the bottom cover taken from direction X in FIG. 1.  
         [0018]    [0018]FIG. 6 shows the top view of the top cover.  
         [0019]    [0019]FIG. 7 shows the side view of the top cover.  
         [0020]    [0020]FIG. 8 shows the cross-section C-C of the top cover.  
         [0021]    [0021]FIG. 9 shows the cross-section D-D of the top cover.  
         [0022]    [0022]FIG. 10 shows the back view of the bottom cover taken from direction Y in FIG. 6.  
         [0023]    [0023]FIG. 11 shows the top view of the frame.  
         [0024]    [0024]FIG. 12 shows the side view of the frame.  
         [0025]    [0025]FIG. 13 shows the bottom view of the frame.  
         [0026]    [0026]FIG. 14 shows the back view of the frame taken from direction E in FIG. 11.  
         [0027]    [0027]FIG. 15 shows the front view of the frame taken from direction F in FIG. 11.  
         [0028]    [0028]FIG. 16 shows the assembly process for the package.  
         [0029]    [0029]FIG. 17 shows the assembly parts for PC cards.  
         [0030]    [0030]FIG. 18 shows the plan view of the assembled package with hidden lines.  
         [0031]    [0031]FIG. 19 shows the side view of the assembled package with hidden lines.  
         [0032]    [0032]FIG. 20 shows the bottom view of the assembled package with hidden lines.  
         [0033]    [0033]FIG. 21 shows the plan view of the assembled package without hidden lines.  
         [0034]    [0034]FIG. 22 shows the side view of the assembled package without hidden lines.  
         [0035]    [0035]FIG. 23 shows the bottom view of the assembled package without hidden lines.  
         [0036]    [0036]FIG. 24 shows the cross-sectional view of the assembled package.  
         [0037]    [0037]FIG. 25 shows a three-dimensional view of a side portion of the frame. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0038]    Throughout the drawings like reference numerals refer to like elements. The terms “top” and “bottom” are used to distinguished between the two covers. The use of the terms does not mean that the package will always be oriented with the “top” cover above the “bottom” cover. Either position of these covers are considered to be within the scope of the invention.  
         [0039]    A typical package of the present invention is depicted in FIG. 17. The package comprises a top cover  2 , a printed circuit board (PCB)  4 , a frame  6 , and a bottom cover  8 . The top cover  2  and the bottom cover  8  are attached to the frame  6  through a novel locking mechanism to be described later in detail. The package contains and fixes in place a PCB  4 .  
         [0040]    FIGS.  1 - 5  depict details of the bottom cover  2 . The bottom cover  2  is preferably a substantially rectangular piece of metal containing a front side  14 , a backside  16 , and lateral sides  18  and  19 . The surface  11  of the bottom cover is optionally raised in relation to the lateral sides  18  and  19  and the backside  16  in order to accommodate a PCB  4  and other components. The lateral side has alternating hooks  12 . The hooks are preferably double folded hooks shown in FIG. 4. The hook comprises a first fold surface  40  and a second fold surface  42 . The termination of the second fold surface  42  preferably contains a segmented tab  24  that serves as a guide to precisely position and to lock the bottom cover  2  with the frame  6 . The segmented tab  24  is a raise portion at the terminal side of the second fold surface  42  (see FIG. 2). The portion of the lateral sides not containing a hook, referred henceforth as flaps  10 , preferably contain a slight bend  30  at the flap termination (FIG. 3). On the lateral sides  18  and  19  are also located hold down tabs  20  towards the backside (see FIG. 2). Friction tab  22  is located at the junction of the lateral sides  18  and  19  and the backside  16 .  
         [0041]    FIGS.  6 - 10  depict details of the top cover  8 . The top cover  8  is substantially identical to the bottom cover  2  with corresponding front side  64 , backside  66 , and lateral sides  68  and  69 . The surface  61  of the bottom cover is optionally raised in relation to the lateral sides  68  and  69  and the backside  66  in order to accommodate a PCB  4  other components. The lateral sides  68  and  69  containing alternating hooks  62  and flaps  60 . The location of the hooks  62  and flaps  60  of the top cover  8  are opposite to the location of hooks  12  and flaps  10  on of the bottom cover  2 . The positions are shown in FIGS. 1 and 6 where the cross-section C-C of the top cover  8  is at the same position as the cross-section A-A of the bottom cover  2 . The cross-section C-C contains hooks (see FIG. 8) while the cross-section A-A contains flaps (see FIG. 3). Also, the hooks  62  of the top cover are preferably double folded hooks with segmented tabs  74 . The hook comprises a first fold surface  80  and a second fold surface  82 . The segmented tabs  74  are raised portion and the terminal of the second fold surface  82  (see FIG. 7). The flaps  60  of the top cover preferably contain a slight bend  90  at the flap termination (FIG. 9). Correspondingly, the top cover  8  also contains a hold down tab  70  and friction tab  72  locating at the same position as those of the bottom cover  2  as shown in FIG. 7.  
         [0042]    Both the top cover  8  and the bottom cover  2  may be constructed of stamped metal such as aluminum or stainless steel. Stamping provides lower manufacturing cost than forged or die cast parts; and metal is preferable in order to provide strength and conductivity for shielding of the PCB  4 .  
         [0043]    While the material for the covers is chosen to be stamped metal, there is no requirement that it be so. Any rigid material will suffice. However, if the cover is of a conductive material, it will serve to reduce EMI, RF and ESD problems, these being factors which electronic devices seek to minimize. It should be further noted that conductive material cannot be eliminated completely as PCMCIA requires a grounding point. The covers  2  and  8  are generally mirror images of each other, but may not be in certain applications.  
         [0044]    An optional addition to the present invention is to coat the interior of the covers  2  and  8  with a thin layer of a non-conductive material. This allows the finished product to have a conductive exterior with a non-conductive interior, thus isolating the conductivity of the interior of the package. Shielding can also be achieved by metallyzed, metal-plated, or conductive plastic material.  
         [0045]    FIGS.  11 - 15  and  25  depict details of the frame  6 . The frame  6  is substantially U-shaped and comprises a front side  114 , a backside  116 , lateral sides  118  and  119 , topside  120 , and bottom side  122 . The lateral sides have alternating latches  110  and slots  112 . The latches  110  are designed to fit with the hooks  12  and  62  of the top and bottom covers  2  and  9 . The latches  110  and slots  112  are located on both the topside  120  and the bottom side  122  of the frame  6 . Preferably, a topside slot is adjacent to a bottom side latch and vice versa (see FIG. 12). FIG. 25 shows the three-dimensional view of a side ( 118  or  119 ) of the frame. The latch is preferably shaped such that a hook ( 12  or  62 ) of the top or of the bottom cover conforms to the shape of the latch. The latch preferably has a recess  121  on the inner side  250  (see FIG. 25) that matches the segmented tab ( 24  or  74 ) of the hook ( 12  or  62 ) to precisely position the hook and to lock it in place. Towards the backside  116 , the frame preferably has notches  111  that are capable of engaging the hold down tabs ( 20  or  70 ) when the cover is in place. The frame also has cut out slits  113  on the backside  116  to engage the friction tabs  22  and  72  to hold the cover in place.  
         [0046]    The frame  6  in a preferred embodiment is constructed of any plastic material such as polycarbonate, nylon, thermal plastic, or various types of engineered plastics. In other embodiments, conductive polymer can also be used by itself or in conjunction with non-conductive plastic. As a further option, the material of the frame  6  can be a metallic material such as aluminum or stainless steel.  
         [0047]    [0047]FIG. 16 illustrates the assembly process of the present invention. In step  1 , the bottom cover  2  is positioned onto the frame  6  with the hooks  12  inserted inside the slots  112  on the bottom side  122  of the frame  6 . In step  2 , the bottom cover  2  is slid a short distance along the length of the frame  6  to engage the hooks  12  and the latches  110 , the hold down tabs  20  and  70  to the notches  111 , and the friction tabs  22  and  72  to the slits  113 . In this half assembled position (step  3 ), the hooks  12  which are shaped to conform to the latches  110  engages the latches and are held in place by friction between the frame  6  and the bottom cover  2 . Further, in a preferred embodiment, when the segmented tabs  24  of the hooks  12  snap into and engage the recesses  121  on the back sides  250  of the latches  110 , frictional force naturally stops the cover and locks it in place. The assembly of the top cover (steps  4  and  5 ) is similar to that of the bottom cover. In step  4 , the top cover  8  is positioned onto the frame  6  with the hooks  62  inserted inside the slots  112  on the topside  120  of the frame  6 . In step  5 , the bottom cover  8  is slid a short distance along the length of the frame  6  to engage the hooks  62  to the latches  110  to complete the assembly process. Also, in a preferred embodiment, when the segmented tabs  74  of the hooks  62  snaps into and engaged the recesses  121  of the latches  110 , frictional force naturally stops the cover and locks it in place.  
         [0048]    FIGS.  18 - 24  depict details of the assembled package with (FIGS.  18 - 20 ) and without (FIGS.  21 - 24 ) hidden lines to clearly show the relationship between the parts of the package. Note that at the back end of the package shown in FIG. 24, there is a gap  240  between the top cover  8  and the bottom cover  2 . When a PCB  4  (not shown the FIG. 24) is present, this gap is designed to accommodate a connector, such as a  68 -pin connector or other suitable connectors to attach the PCB to a computer or other devices.  
         [0049]    Although certain presently preferred embodiments of the invention have been specifically described herein, it will be apparent to those skilled in the art to which the invention pertains that variations and modifications of the various embodiments shown and described herein may be made without departing from the spirit and scope of the invention. Accordingly, it is intended that the invention be limited only to the extent required by the appended claims and the applicable rules of law.