IC card connector shield grounding

A system is described for electrically grounding plug and receptacle connectors (12, 16, FIG. 3) as they mate, which occupies minimal space that would otherwise be occupied by regular pin-and-socket contacts, and which isolates sparks created during ground connections. Each connector has a dielectric housing (54, 80) lying at the end of a circuit board (60, 82). The receptacle connector has a shield (100) extending around its dielectric housing, the shield having a tab (162) that is soldered to a grounded trace (160) on the corresponding circuit board. The plug connector carries a plug ground member (142) that has a front end (144) for engaging the shield on the connector member when the connectors mate, the plug ground member having a rear end forming a tab (172) that is soldered to a grounded trace (174) on its corresponding circuit board. The plug ground member lies in a groove (140) of the dielectric housing, with a resilient bent portion (146) projecting out of the groove. The connector housing shield has a strip (120) which is bent 180.degree. to extend within a side of the shield.

BACKGROUND OF THE INVENTION 
IC cards, which are of about the same width and length as a typical credit 
card, have dimensions defined by PCMCIA (Personal Computer Memory Card 
International Association). Such cards have a width and length of 54 mm 
and 85.6 mm, respectively, with three different types having thicknesses 
of 3.3 mm, 5 mm, and 10.6 mm. Recent cards allow connection of the card to 
a local area network (LAN) by providing a receptacle connector at the rear 
of the IC card. An adapter cable assembly has a plug connector at its 
front end that plugs into the receptacle connector at the rear of the 
card. U.S. Pat. Nos. 5,387,110 and 5,411,402 describe plug connectors of 
this type, which have latches at their middles. 
Newer IC cards require greater numbers of contacts. A latching mechanism 
for retaining a plug connector to the rear of the card, may occupy space 
that otherwise could hold several contacts, which makes even less space 
available. When the plug and receptacle contacts mate, electrical ground 
planes or grounds of the plug and receptacle connectors and/or their 
corresponding circuit boards must be connected. If grounding is to occur 
through regular pin and socket contacts, then such grounding contacts may 
not have sufficient current-carrying capacity, and they waste space that 
could otherwise be occupied by signal contacts. Also, there may be a 
substantial buildup of static electricity in the plug or receptacle, and a 
spark created as contacts closely approach each other, could damage 
adjacent contacts, especially in the case of pin contacts wherein there is 
no insulation between the free ends of adjacent pins. Plug and receptacle 
connectors which facilitated grounding to each other while minimizing the 
amount of space required for the grounding connections and while isolating 
any sparks created during mating from signal-carrying contacts, would be 
of value. 
SUMMARY OF THE INVENTION 
In accordance with one embodiment of the present invention, plug and 
receptacle connectors and their combination are provided with means for 
connecting together the grounds of the connectors and/or corresponding 
circuit boards in a manner that minimizes space required for mating 
grounding terminals while protecting signal contacts from sparks. The 
receptacle connector includes a grounded sheet metal shield surrounding 
the dielectric receptacle housing, while the plug connector has a grounded 
member that engages the receptacle shield during mating. The receptacle 
shield has a tab that is joined, as by soldering, to a grounded trace on 
its corresponding circuit board, while the plug grounded member has a tab 
that is joined to a grounded trace on its corresponding circuit board. The 
plug grounded member has a terminal portion that lies in a groove at a 
side of the plug dielectric housing, with the plug terminal portion having 
a part that projects slightly from the groove to engage the shield. The 
shield includes an elongated strip that is bent about 180.degree. and 
which engages the projecting part on the plug ground member. 
The novel features of the invention are set forth with particularity in the 
appended claims. The invention will be best understood from the following 
description when read in conjunction with the accompanying drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIG. 1 illustrates a connector system 10 that includes a plug connector 12 
lying at the front of a cable 14, and a receptacle connector 16 lying at 
the rear of an IC card 18 of the PCMCIA type. Such IC cards generally have 
a width of 54 mm and length of 85.6 mm, and a thickness that may range 
between 3.3 mm and 10.5 mm, with the particular card illustrated being a 
type II card which has a thickness of 5 mm. The plug connector has 
laterally opposite sides 24, 26 front and rear ends 30, 32 and a top and 
bottom 20, 22, and is mated to the receptacle connector by moving the plug 
connector forwardly in the direction F along a plug connector axis 34. The 
connectors are symmetrical about a vertical plane extending through the 
axis 34. During mating, socket contacts 36 of the plug connector mate with 
pin contacts 38 of the receptacle connector. Forward and rearward 
directions are indicated by arrows F, R, up and down directions are 
indicated by arrows U, D, and lateral directions are indicated by arrow L. 
As shown in FIG. 2, each connector has a latch region 50, 52, which is 
designed to contain a latch mechanism. A variety of latch mechanisms are 
available, such as those shown in U.S. Pat. Nos. 5,387,110 and 5,411,402. 
FIG. 2 indicates a latch mechanism in phantom lines, by a latch 40 on the 
plug connector and a latch-receiving recess 42 on the receptacle 
connector. 
The plug connector 12 has a dielectric plug housing 54 with front and rear 
portions 56, 58 and laterally opposite side walls 57, 59. The rear portion 
58 is connected to a plug circuit board 60. The plug connector has two 
laterally-extending rows of socket-type plug contacts 36. The circuit 
board has a front portion 64 that holds a laterally (in direction L) 
extending row of conductive traces 66 on both its upper and lower faces, 
with the socket contacts having tails 70 that are joined to the traces as 
by soldering. 
The receptacle connector 16 has a dielectric receptacle housing 80, and the 
card 18 which includes a receptacle circuit board 82. The receptacle 
connector has a row of receptacle contacts 38 with pin-type rear ends 86. 
Each receptacle contact has a middle 90 anchored in the receptacle housing 
80 as by being molded in place, and has a tail 92 at its front end. The 
circuit board 82 has a row of electrically conductive traces 94 to which 
the contact tails are joined, as by soldering. The circuit board is shown 
having two rows of traces 94, 96, one for contacts of the upper row and 
one for contacts of the lower row. 
As shown in FIG. 3, the receptacle connector 16 includes a sheet metal 
shield 100 that lies immediately above, below, and on laterally opposite 
sides of the receptacle housing 80. As also shown in FIG. 8, the 
receptacle housing 80 has a top and bottom 102, 104 and opposite sides 
106. Referring to FIG. 3, it can be seen that the receptacle housing forms 
a hollow region or hollow 110 at its rear end, and the pin-type free ends 
86 of the receptacle contacts lie within the hollow. The presence of the 
shield is especially important where high frequency signals are carried. 
Applicant forms the shield with a ground receptacle terminal or terminal 
portion 120 in the form of a bent elongated strip of the sheet metal of 
which the shield is formed. As shown in FIGS. 6 and 7, the strip extends 
from a rear edge 122 of the shield and has a substantially 180.degree. 
bend 124 near where it emerges from the end, with the rest of the strip 
extending substantially forwardly and lying within the rest of the shield. 
As indicated in FIG. 8, the dielectric receptacle housing 80 has a slot or 
groove 130 that receives the bent elongated strip shown in FIG. 7 at 120. 
The bent strip or receptacle ground terminal provides a smooth surface and 
also adds resilience to aid in contacting a grounded terminal portion of 
the plug connector. 
As shown in FIG. 3, the plug connector housing 54 has a top and bottom and 
opposite sides, and has a recess or groove 140 in each of its sides. A 
plug ground member 142 has a forward terminal portion 144 lying in the 
groove, with a bent contact part 146 thereof projecting sidewardly out of 
the groove. The sheet metal of the forward terminal portion 144 lies in 
substantially vertical planes, and has a greater vertical height than its 
thickness. When the connectors mate, the plug housing 54 fits within the 
hollow 110 at the rear of the receptacle connector housing. During such 
mating, the projecting part 146 of the plug ground member engages the bent 
strip 120 formed on the shield of the receptacle connector. Such 
engagement occupies very little of the lateral width of the connector, 
which is usually less than the space that would be occupied by a pin-type 
terminal 84 (plus the space required around it). Also, any sparks created 
during mating of the projection 146 with the bent strip 120 is largely 
shielded from the signal-carrying contacts by the dielectric plug housing 
54. The grounded terminal portions 144, 120 have a large cross-section 
which is usually greater than that of the pin free ends 86 to carry large 
grounding currents. Furthermore, the grounding of the receptacle occurs at 
the strip 120 which is part of the rest of the sheet metal shield 100, so 
that it is not necessary to provide a connection between a pin type 
contact and the shield or to make any solder or weld joints therealong. 
The receptacle circuit board has an electrically grounded receptacle trace 
160. The sheet metal shield 100 is provided with a tab 162 which is bent 
and which has a ground terminal portion 164 which is joined to the 
grounded trace 160 as by soldering thereto. As can be seen in FIG. 2, the 
grounded trace 160 lies immediately forward of the latch region 52 that 
would be occupied by a cavity 42 to which a latch on the plug connector 
would latch. Accordingly, the space at the trace 160 could not otherwise 
be occupied by contact pads so long as a latch-receiving cavity lies at 
the middle of the connectors. By applicant providing the grounded trace 
160 on this location, the grounded trace 160 does not occupy space that 
otherwise would be used, and a wide large current-carrying capacity tab 
can connect to the grounded trace. 
As shown in FIG. 3, the plug ground member 142 has a rear portion 170 that 
forms a tab 172 which is joined to an electrical ground plug trace 174 on 
the plug circuit board 60. The tab can lie at 172A to connect to the 
bottom face of a higher circuit board. 
It can be seen from FIG. 3, that the shield 100 has upper and lower shield 
members 170, 172. The upper shield member is provided with a pair of 
locking ears 175 that project into locking slots formed in the lower 
member. As a result, the shield can be readily placed around the 
receptacle connector housing 80 by moving the lower shield up and the 
upper shield down, until the ears 175 snap into the slots 176, at which 
time the tab ground portion 164 will lie against the circuit board ground 
trace 160. 
Both the plug housing 54 and receptacle housing 80 are of largely 
parallelepiped shape, with largely parallel top and bottom surfaces and 
largely parallel laterally-spaced opposite sides. The hollow 110 is 
preferably formed so that it has a narrow upper end 180 and a slightly 
wider lower end 182, to form a polarizing keyway that receives a 
correspondingly polarized plug connector housing 54. Applicant prefers to 
make the grounding connection at the opposite ends of the wider lower 
housing ends, where the grounding contacts are spaced slightly more from 
the signal-carrying contacts. 
In a system that applicant has designed, the shield 100 had a lateral width 
of 1.14 inch, a height of 0.17 inch, and a front-to-rear length (not 
including tab 162) of 0.314 inch. The upper and lower interrupted rows of 
contacts each included eighteen contacts spaced at a 0.050 inch pitch. 
Although terms such as "upper", "lower", etc. are used to aid in the 
description of the parts as illustrated, the connectors and other parts 
can be used in any orientation with respect to Earth's gravity. 
Thus, the invention provides plug and receptacle connectors and the 
combination of the connectors and circuit boards of a plug and an 
electronic device such as an IC card, with an enhanced electrical 
grounding arrangement. The receptacle connector is provided with an 
electrically grounded sheet metal shield, while the plug connector is 
provided with a plug grounding member for engaging the shield. The 
engaging portions preferably lie at opposite sides of the respective 
housings, and preferably within the wider keyways or keys thereof. The 
shield has a tab that is joined to a grounded conductive trace on a 
circuit board associated with the receptacle connector. The plug grounding 
member has a rear portion forming a tab that is joined to a grounded trace 
on the plug circuit board. The plug grounding member preferably has a 
forward terminal portion lying in a groove at the side of the dielectric 
plug housing, and has a bent laterally projecting portion. The shield of 
the receptacle connector preferably has an elongated strip that is bent 
about 180.degree. to form a terminal for engaging the corresponding 
terminal formed by the plug grounding member. 
Although particular embodiments of the invention have been described and 
illustrated herein, it is recognized that modifications and variations may 
readily occur to those skilled in the art, and consequently, it is 
intended that the claims be interpreted to cover such modifications and 
equivalents.