Giga-bit interface convertor bracket with enhanced grounding

A giga-bit interface convertor module bracket assembly having upper and lower ground springs. The upper ground spring has upper wing-shaped springs in the upper part of the front opening of the bracket assembly and a pair of upper spring tabs on the interior of the bracket assembly. The lower ground spring has lower wing-shaped springs in the lower part of the front opening of the bracket assembly and a pair of lower spring tabs on the interior of the bracket assembly. When a giga-bit interface convertor module is inserted in the bracket assembly through the front opening, the upper and lower spring tabs bias against the top and bottom walls of the giga-bit interface convertor module to provide grounding thereto. Additionally, the upper and lower wing-shaped springs contact with a front panel of an enclosure or bracket or an electronic card on which the bracket assembly sits. The lower ground spring is provided with a bottom ground spring to contact the electronic card for grounding.

BACKGROUND OF THE INVENTION
 1. Field of the Invention
 The present invention relates to an improved bracket for a giga- bit
 interface convertor. More particularly, the bracket provides an improved
 grounding to a PCI card, daughter card, motherboard and the like.
 2. Background
 A bracket provided in accordance with the present invention is designed to
 contain a universal giga-bit interface convertor (GBIC) module. A giga-bit
 interface convertor is a high-speed data transfer switch that can be used
 to interconnect work stations, main frames, supercomputers and storage
 devices. It can be employed at various locations in a computer network
 where giga-bit data is transferred. A high-speed data transfer switching
 is used in many applications such as Video on Demand and interactive
 video, which require faster access to large data storage systems such as
 DASDs and RAIDs.
 FIG. 1 shows an example of a network where giga-bit interface convertors
 are employed. A mass storage 1 may be DASD/RAID mass storage. The mass
 storage 1 is connected to a server 3. Data transfer rate is in the order
 of Gbits/sec. For instance, the rate may be 1.0625 Gbits/sec. with
 provisions for 2.125 Gbits/sec. and 4 Gbits/sec. The server 3 is in turn
 connected to a hub or switch 5 by a giga-bit interface convertor module 9.
 The giga-bit interface convertor module 9 plugs into a guide assembly or
 bracket (FIG. 2) provided on a motherboard 6. In place of a motherboard,
 any printed card may be employed. A plurality of work stations 7 are
 provided to connect with the hub 5 for giga-bit data transfer.
 FIG. 2 shows a giga-bit interface convertor module 11, a bracket or guide
 assembly 15 and an interface expansion card 17. The giga-bit interface
 convertor module 11 shown here is of a type which employs twenty-position
 straddle mount plug 19 on one end and a duplex copper interface 21 on the
 other. It is noted that the interface can be fiber optics rather than
 copper. The plug end 19 is inserted through an opening 23 in the front of
 the guide assembly 15 until the plug connects to a receptacle 29.
 Simultaneously, detents on the giga-bit interface convertor module 11 snap
 into place on the guide assembly 15. A pair of channels 25 are defined on
 longitudinally extended sides of the module 11 and a complementary pair of
 bars 27 are provided on the interior sides of the guide assembly 15 for
 mating with the channels 25 so that the module 11 may be suitably aligned
 and guided toward the rear of the guide assembly 15. The plug end 19 of
 the module 11 is received by the receptacle 29, which in this case is a
 twenty-position right-angle receptacle, provided on the interface
 expansion card 17.
 As shown in FIGS. 3-5, the guide assembly 15 has an integrally formed
 housing 16, which is made of thermoplastic. When the guide assembly 15 has
 no module plugged into it, a self-closing metallic dust door 31 shields
 the interior of the interface expansion card 17 from the exterior
 environment. The dust door 31 is spring-biased with an expansion card
 spring 100 (FIG. 5) provided on one side of the guide assembly 15. Upper
 and lower grounding clips 33 and 35 are provided at the opening 23 of the
 guide assembly 15 to make contact with both the module 11 and the
 interface expansion card 17. The upper and lower grounding clips 33 and 35
 are in turn provided with a plurality of tabs 32, 34 (see FIG. 3) which
 are slightly raised from the rest of the grounding clips 33, 35. Although
 this is intended to provide a ground path as explained below, only a
 limited and partial ground path is established.
 The guide assembly 15 employs integrally-formed hold-down latches 37 to fit
 in corresponding hold-down latch apertures 38 formed in the interface
 expansion card 17. To provide alignment and stability, the guide assembly
 15 also employs two pairs of alignment knobs 39 adjacent the hold-down
 latches, which fit in corresponding knob apertures 41 formed in the
 interface expansion card 17. Further, two guide assemblies, each of which
 is identical to the guide assembly 15, may be mounted side-by-side on
 interface expansion card 17.
 The above-described conventional guide assembly 15, however, does not
 provide grounding to the interface expansion card 17 and only a very
 limited grounding to the giga-bit interface convertor module 11 and to the
 interface panel, and requires a significant amount of re-engineering
 before it can be used in a commercial environment. For instance, an extra
 gasket must be provided to aid the dust door 31 with its electromagnetic
 interference attenuation. The guide assembly 15 has problems with
 electromagnetic interference emanating from the plugged-in module 11
 because the guide assembly 15 does not adequately contain electromagnetic
 interference. Specifically, the giga-bit interface convertor, module 11
 needs a high frequency, low impedance path to ground, and the opening,
 through which the giga-bit interface convertor module 11 is accessible to
 the user, needs to be shielded when the giga-bit interface convertor
 module 11 is not installed.
 SUMMARY OF THE INVENTION
 A guide assembly for a giga-bit interface convertor module is provided
 having a pair of ground springs: an upper ground spring and a lower ground
 spring. The upper ground spring is provided with an upper wing-shaped leaf
 spring portion at the front of the guide assembly, which makes contact
 with front panel of an electronic card enclosure or bracket which houses
 the giga-bit interface convertor. The upper ground spring is also provided
 with a pair of upper grounding tabs which are located on the upper
 interior wall adjacent the front opening of the guide assembly. In this
 way, a ground path for the top of the giga-bit interface convertor module
 is established. In addition, the top of the opening in the front panel of
 the enclosure is divided into smaller slots, thereby lowering high
 frequency emissions.
 Similarly, the lower ground spring is provided with a lower wing-shaped
 spring portion at the front of the guide assembly to make contact with the
 front panel. The lower ground spring is also provided with a pair of lower
 grounding tabs located on the lower interior wall of the guide assembly
 adjacent the front opening thereof. In this way, a ground path for the
 bottom portion of the giga-bit interface convertor module is established,
 and the bottom of the opening in the front panel is divided into smaller
 slots, thereby further lowering high frequency emission. The lower ground
 spring is further provided with a bottom ground spring portion which
 protrudes from the bottom of the guide assembly. The bottom ground spring
 portion makes contact with the electronic card to which the bracket is
 mounted. Additional electromagnetic interference attenuation may be
 attained by this contact.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
 FIGS. 6 and 7 show a bracket or guide assembly 50 according to the present
 invention. The bracket 50 has a bracket housing 51 which is formed from a
 plastic material. The bracket 50 is provided with a pair of ground
 springs: an upper ground spring 80 and a lower ground spring 90. Both
 ground springs 80, 90 may be made from any number of tin-plated sheet
 metal or beryllium copper materials.
 The upper ground spring 80 has two upper wing-shaped spring portions 53
 located at the upper rim 54 of the front opening 55 of the bracket housing
 51, and a pair of upper grounding spring tab portions 63A and 63B located
 on the interior front wall portion 77 of the bracket housing 51. A
 substantially flat central portion 52 is located between the two upper
 wing-shaped spring portions 53. The upper wing-shaped spring portions 53
 make contact with the front panel of electronic card enclosure which
 houses the bracket 50 and the giga-bit interface convertor module.
 The upper grounding spring tab portions 63 come into contact with the
 giga-bit interface convertor module when the module is inserted in the
 bracket housing 51. The upper grounding spring tab portions 63 are
 inclined as shown in FIG. 7 so that when the giga-bit interface convertor
 module is inserted in the bracket housing 51, the module easily slides in.
 The upper grounding spring tab portions 63 are biased against the top of
 the giga-bit interface convertor module, thereby making contact with the
 top of the module to establish a ground path. In this way, the upper
 ground spring 80 provides a ground path for the top of the giga-bit
 interface convertor module to the front panel of the electronic card
 enclosure. The upper ground spring 80 also divides the top of the opening
 in the front panel into smaller slots with the effect of lowering high
 frequency emissions. Another ground spring portion, a top ground spring
 portion 69, is formed on the upper ground spring 80 on top of the bracket
 housing 51. The top ground spring portion 69 holds the upper ground spring
 80 and prevents it from disengaging from the bracket housing 51.
 The lower ground spring 90 is provided with a pair of lower wing-shaped
 spring portions 57, a pair of lower ground spring tab portions 61 and a
 bottom ground spring portion 67. The lower wing-shaped spring portions 57
 are provided on the lower rim 58 of the front opening 55 in the bracket
 housing 51. As with the upper grounding spring 80, the lower wing-shaped
 spring portions 57 come in contact with the front panel of the electronic
 card enclosure which accommodates the bracket 50 and the giga-bit
 interface convertor module to establish a ground path. In this manner, the
 upper and lower ground springs 80, 90 ensure that high frequency effects,
 such as skin effect, are minimized.
 The lower ground spring tab portions 61 are provided on a lower interior
 wall 75 of the bracket housing 51 near the front opening 55. The lower
 ground spring tab portions 61 are sloped upward away from the front
 opening 55 of the bracket housing 51. They are also biased against the
 giga-bit interface convertor module so that a ground path is established
 between the lower ground spring tab portions 61 and the bottom wall of the
 giga-bit interface convertor module when the giga-bit interface convertor
 module is inserted through the front opening 55 of the bracket housing 51
 and comes in contact with the lower ground spring tab portions 61.
 In this way, the lower ground spring 90 provides a ground path to the
 bottom of the giga-bit interface convertor module to the front panel of
 the electronic card enclosure. It also divides the bottom of the opening
 in the front panel into smaller slots, thereby lowering high frequency
 emissions.
 The bottom ground spring portion 67 substantially longitudinally extending
 from one side to the other of the bracket housing 51 is formed on the
 lower ground spring 90 on the bottom side of the bracket housing 51 as
 shown in FIG. 7. The bottom ground spring portion 67 extends downward to
 make contact with a ground plane of the electronic card such as a HBA
 card, an S-bus, a PCI card, a daughter card or a motherboard and the like,
 thereby further enhancing electromagnetic interference attenuation between
 the bracket housing 51 and the electronic card on which the bracket
 housing 51 is mounted.
 As shown in FIGS. 6 and 7, two pairs of alignment knobs 64A, 64B, 66A, 66B
 are provided on the underside of the bracket housing 51. All of the
 alignment knobs 64A, 64B, 66A, 66B are designed to be longer than a pair
 of hold-down latches 65 which are provided on the underside of the bracket
 housing 51. This aids in the assembly of the bracket housing 51 on the
 interface expansion card panel. The alignment knobs 64A, 64B provided on
 the left side of the bracket housing 51 and the other two alignment knobs
 66A, 66B provided on the right side of the bracket housing 51 may be
 located at same distances away from the front end of the bracket housing
 51. In the alternative, the alignment knobs 64A, 64B may be located at
 different distances from the ends of the bracket housing 51 so as to be
 off set from the corresponding pair of alignment knobs 66A, 66B on the
 other side, as shown in FIG. 7. The right rear alignment knob 66B is
 located substantially at the very end of the bracket housing 51, whereas
 the left rear alignment knob 63B is located a short distance from the back
 end of the bracket housing 51. Similarly, the right front alignment knob
 66A and the left front alignment knob 63A are off-set from each other. As
 with the alignment knobs 64A, 64B, 66A, 66B, the right and left hold-down
 latches 65 may be off-set from each other as shown in FIG. 7.
 The bracket housing 51 defines upper and bottom openings 60, 62 so that
 vents 64 (FIG. 2) on the giga-bit interface convertor module are not
 blocked. A rear portion 71 of the bracket housing 51 provides stability to
 the bracket 51. A pair of side walls 73 of the bracket housing 51 extend
 from the front bracket opening 55 toward the rear end of the bracket
 housing 51.
 The guide assembly 50 is configured so as to be compatible with existing
 computer components. In particular, mechanical interface to the plastic
 bracket assembly 50 meets the industry GBIC standard, which is published
 as "Gigabit Interface Convertor (GBIC)" Revision 5.1, dated and printed
 Jul. 6, 1998, by Sun Microsystems Computer Company, Vixel Corporation,
 Compaq Computer Corporation and AMP Incorporated. The height of the
 bracket 50 above and below the electronic card meets the PCI standards.
 Retrofitting is possible with the guide assembly 50 according to the
 present invention with minimal redesign of the interface expansion card.
 While specific embodiments of the invention have been described, it will be
 apparent that obvious variations and modifications of the invention will
 occur to those of ordinary skill in the art from a consideration of the
 foregoing description. For example, the present invention can be adopted
 for use with other types of switch modules. It is therefore desired that
 the present invention be limited only by the appended claims and
 equivalents.