Patent Document

BACKGROUND 
   Wireless devices, such as personal data assistants, may transmit and receive data via a wireless network (e.g., an 802.11x network) using removable Peripheral Component Interconnect (“PCI”) radio cards or internal Mini PCI radio cards. Use of the Mini PCI radio card is favorable in smaller systems in which standard-sized PCI radio cards cannot be used due to spatial and/or mechanical constraints. 
   Today, a large percentage of the 802.11 radios are implemented in the Mini-PCI format because of its reduced size, high performance, modularity and lower cost. The Mini PCI format has been created to promote interchangeability of 802.11 radios between host systems, and to permit regulatory agencies to approve the radios independent of the host systems. The Mini PCI format includes several form factors including Types I, II and III, with Type III being the most common. The Type III Mini PCI radio card generally mates with a 124-pin card connector on a printed circuit board (“PCB”) which is similar to the SO-DIMM type. 
   Although coupling the radio card to the card connector generally provides adequate electrical performance, small movements of the wireless device (e.g., a shock, vibration, shaking, etc.) may cause the radio card to lose/degrade its electrical connection with the card connector impairing functionality or disabling the wireless communications capability of the wireless device. 
   SUMMARY OF THE INVENTION 
   The present invention relates to an apparatus for releasably coupling an electrical component to a circuit board comprising a frame and at least one tab. The frame releasably couples to the electrical component and circumscribes at least a portion of a perimeter of the electrical component when coupled thereto. The at least one tab mates with a tab receiving slot in the circuit board to releasably couple the frame to the circuit board. When the electrical component is coupled to the frame, a portion of the electrical component opposite the circuit board is exposed. 

   
     BRIEF DESCRIPTION OF DRAWINGS 
       FIG. 1  shows an exemplary embodiment of a circuit assembly according to the present invention; 
       FIG. 2   a  shows a top view of an exemplary embodiment of a card mounting bracket according to the present invention; 
       FIG. 2   b  shows a side view of an exemplary embodiment of a card mounting bracket according to the present invention; 
       FIG. 2   c  shows a rear view of an exemplary embodiment of a card mounting bracket according to the present invention; 
       FIG. 3  shows a schematic view of a card mounting bracket and a printed circuit board according to the present invention; 
       FIG. 4  shows a schematic view of a card mounting bracket and a printed circuit board according to the present invention; 
       FIG. 5  shows a schematic view of a radio card, a card mounting bracket and a printed circuit board according to the present invention; 
       FIG. 6  shows a schematic view of a radio card, a card mounting bracket and a printed circuit board according to the present invention; 
       FIG. 7  shows a close-up view of a retaining member on a card mounting bracket and a radio card according to the present invention; 
       FIG. 8  shows a schematic view of a radio card and a card mounting bracket mounted to a printed circuit board according to the present invention; 
       FIG. 9  shows a schematic view of a card mounting bracket and a printed circuit board mounted to a reverse side thereof according to the present invention; 
       FIG. 10  shows a schematic view of a card mounting bracket and a printed circuit board mounted to a reverse side thereof according to the present invention; and 
       FIG. 11  shows a schematic view of a radio card, a card mounting bracket and a printed circuit board mounted to a reverse side thereof according to the present invention 
   

   DETAILED DESCRIPTION 
   The present invention may be further understood with reference to the following description and the appended drawings, wherein like elements are provided with the same reference numerals. The present invention describes a card holder arrangement for mounting an external component to a printed circuit board (“PCB”). Although, the exemplary embodiment will be described with reference to a PCB utilized in a wireless computing device, those of skill in the art will understand that the card holder arrangement of the present invention is scalable for use with larger/smaller external components (e.g., memory chips, standard PCI cards, etc.) and in larger/smaller computing devices (e.g., PCs, laptops, etc.). 
     FIG. 1  shows an exemplary embodiment of a circuit assembly  10  according to the present invention. The assembly  10  according to this embodiment is utilized in a wireless computing device such as, for example, an image/laser-based scanner, an RFID reader/tag, a laptop, a phone, a PDA, a tablet, a network interface card, etc. In alternative embodiments, the assembly  10  may be utilized in a stationary computing device such as a PC. That is, any computing device may utilize the assembly  10  for coupling an external component to a circuit board providing additional functionality to the computing device. 
   The assembly  10  includes a printed circuit board (“PCB”)  12 , an external component (e.g., a radio card  14 ) and a component mounting bracket  16 . The PCB  12  may be any size, shape and/or design (e.g., form factor) known to those of skill in the art. As one of ordinary skill in the art will understand, the PCB  12  may include any number and variety of electrical components (e.g., processors, memory, etc.) coupled to either surface of the PCB  12  (e.g., top and/or bottom). In the exemplary embodiment, the PCB  12  includes a card connector  18  for sustaining an electrical connection with the radio card  14 . The card connector  18  includes pins which, when in contact with pins of the radio card  14 , allow for an exchange of electrical signals between the radio card  14  and electrical components on the PCB  12 . 
   At least one pair of slots  20  are formed adjacent to the card connector  18  allowing the bracket  16  to be mounted to the PCB  12 . In the exemplary embodiment, the PCB  12  includes two pairs of slots  20  which allow two component mounting brackets  16  to be mounted thereto. Thus, in the exemplary embodiment, two radio cards  14  may be mounted to substantially similar areas of the PCB  12 , on opposite sides thereof. However, those of skill in the art will understand that the pairs of slots  20  may be formed in any suitable areas on the PCB  12  for mounting the brackets  16  and corresponding radio cards  14  thereto (e.g., on both sides of the PCB  12 ). Furthermore, a number of the pairs of slots  20  preferably correspond to a number of radio cards  14  to be mounted to the PCB  12 . 
   An exemplary embodiment of the bracket  16  is shown in  FIGS. 2   a - 2   c . The bracket  16  is preferably a frame formed of a single piece of material (e.g., plastic, rubber, ceramic, sheet metal, etc.) which is mountable to the PCB  12  without requiring mechanical and/or chemical fasteners. As would be understood by those skill in the art, the bracket  16  may be manufactured using any conventional process (e.g., injection molding). Conventional radio card mounting brackets are generally mechanically fastened to the PCB  12 . The bracket  16  according to the present invention allows for toolless assembly of the bracket  16  to the PCB  12  and of the radio card  14  to the bracket  16 . In the exemplary embodiment, the bracket  16  is interlocked to the PCB  12  using the slots  20 . After the bracket  16  is mounted to the PCB  12 , the radio card  14  is coupled to the card connector  18  and secured within the bracket  16 . The bracket  16  prevents the radio card  14  from coming loose from the card connector  18  thereby maintaining its electrical connection with the PCB  12 . 
   The bracket  16  includes a front wall  22 , a rear wall  24  and sidewalls  26 ,  28  enclosing a generally rectangular area  30  sized and shaped to complement the radio card  14 . Those of skill in the art will understand that the arrangement  10  may be of any size and/shape complementary to the size/shape of a component to be retained therein. Similarly, a stack height of the bracket  16  is preferably similar to a stack height of the component secured thereby (e.g., the radio card  14 ). The bracket  16  prevents lateral and vertical displacement of the radio card  14 , as will be described further below. In one exemplary embodiment, the sidewalls  26 ,  28  are designed with a bow shape allowing a tension-extension length therein. The tension-extension length permits the rear wall  24  to move away from the front wall  22  for accommodating slight variances in the length of the radio card  14  which may ensure a snug fit at assembly. 
   An inner face of the rear wall  24  includes ledges  30 ,  32  which preferably have a stack height similar to that of as the card connector  18 . That is, when the radio card  14  is coupled to the card connector  18 , there is preferably a space between the radio card  14  and the surface of the PCB  12 . The radio card  14  rests on the ledges  30 ,  32  to be maintained at the stack height of the card connector  18  providing integrity to the electrical connection. Those of skill in the art will understand that other exemplary embodiments of the bracket  16  may include a single ledge or a plurality of ledges for maintaining the radio card  14  at the stack height of the card connector  18 . 
   The inner face of the rear wall  22  further includes a retaining member  34  centered between the ledges  30 ,  32  at a predetermined height thereabove. The height is preferably equal to at least a thickness of the installed radio card  14 . Thus, when the radio card  14  is depressed onto the ledges  30 ,  32 , the radio card  14  is secured between the retaining member  34  and the ledges  30 ,  32 . The retaining member  34  preferably includes a protruding downward slope providing resistance to the radio card  14  as it is pushed onto the ledges  30 ,  32 . When the radio card  14  is pressed past the slope, the radio card  14  snap-fits between the slope and the ledges  30 ,  32 . Thus, the retaining member  34  and the ledges  30 ,  32  prevent the radio card  14  from moving vertically when coupled to the card connector  18 . 
   As shown in  FIG. 2   b , each of the sidewalls  26 ,  28  includes a notch  36  at a front end thereof and an interlocking tab  38  at a rear end thereof. The notch  36  provides space for a tab of a further bracket to be mounted on a substantially similar portion of the PCB  12 , but on an opposite side thereof. The tab  38  includes a foot  40  which retains the tab  38  within the slot  20 . That is, to lock the bracket  16  to the PCB  12 , the foot  40  is inserted into a portion of the slot  20  which is narrower than a width of the foot  40 . Thus, the bracket  16  cannot be removed from the PCB  12  until the foot  40  is removed from the slot  20 . 
   Referring back to  FIG. 2   a , the radio card  14  is removed from the bracket  16  by applying a compressive force to the sidewalls  26 ,  28 . That is, the sidewalls  26 ,  28  bow outward providing a predetermined clearance between themselves and the radio card  14 . The compressive force distends the rear wall  24  releasing the radio card  14  from the retaining member  34 . The radio card  14  may then be lifted from the bracket  16 . A cut-out  40  is provided in the rear wall  24  to facilitate lifting the radio card  14  from the bracket  16 . 
     FIGS. 3-8  show an exemplary method of mounting the bracket  16  to the PCB  12 , coupling the radio card  14  to the card connector  18  and securing the radio card  14  in the bracket  16 . In  FIG. 3 , the tabs  38  are inserted into the slots  20 . As shown, a wide portion of the slot  20  receives the foot  40  while a narrow portion of the slot  20  retains the foot  40  securing the bracket to the PCB  12 . 
   In  FIG. 4 , the bracket  16  is mounted to the PCB  12  with the tabs  38  interlocked with the slots  20  and the front wall  22  abutting the card connector  18 .  FIG. 5  shows the radio card  14  being coupled to the card connector  18  with the electrical contacts of the radio card  14  contacting corresponding contacts on the card connector  18 . 
   In  FIG. 6 , the radio card  14  is shown with the electrical contacts thereof fully engaged with the contacts of the PCB  12  and the card connector  18  with a first side of the radio card  14  contacting the bracket  16 . At this point, the radio card  14  has not yet been inserted between the retaining member  34  and the ledges  30 , 32 .  FIG. 7  shows the radio card  14  after it has been pushed past the retaining member  34  to secure the radio card  14  within the bracket  16  and prevent vertical displacement of the radio card  14  during use, a shock event, etc. 
     FIG. 8  shows a complete mechanical and electrical assembly of the PCB  12 , bracket  16  and radio card  14 . The bracket  16  is preferably sized to fence-in the radio card  14  and the card connector  18 . When the radio card  14  is coupled to the card connector  18  the bracket  16  is prevented from disengaging the slots  20 , because the radio card  14  prevents movement of the rear wall  24 . Thus, the tabs  38  cannot reach the portion of the slots  20  from which the foot  40  may exit. 
     FIG. 8  also shows that when installed, electrical components on the radio card  14  are exposed. This configuration allows external heat-sinking of hot areas the radio card  14  improving performance and life. For example, a conventional heat sink may be placed adjacent the exposed area of the radio card  14 . In another embodiment, the bracket  16  may be fitted with a cover (not shown) over the area  30  which would aid in electromagnetic shielding and electrostatic discharge protection. 
   As described above, a further radio card  14 ′ may be mounted on an opposite side of the PCB  12  as shown in  FIGS. 9-11 . A bracket  16 ′ is interlocked with slots  20 ′ in a manner substantially similar to that described above in regard to the bracket  16  and the slots  20 . As shown in  FIG. 10 , a notch  36 ′ in the bracket  16 ′ provides clearance for the tab  38  of the bracket  16  mounted on the opposite side of the PCB  12 . This allows the radio card  14  and the further radio card  14 ′ to be mounted in similar positions on opposite sides of the PCB  12 . Thus, multiple radio cards may be stacked on the PCB  12 . The further radio card  14 ′ is mounted to and removed from the bracket  16 ′ in the manner described above. 
   The disclosed exemplary embodiments of the present invention may withstand approximately 0.02 g 2 /Hz of random vibration in all three axises, approximately 20 Hz to 2000 Hz. The exemplary embodiments may also withstand at least a ninety-one (91) centimeter drop to a hard surface (e.g., concrete). 
   While specific embodiments of the invention have been illustrated and described herein, it is realized that numerous modifications and changes will occur to those skilled in the art. It is therefore to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit and scope of the invention.

Technology Category: 3