Input/output connector for portable communication device and process for mounting the said connector

An electrical connector for a portable communication device. The connector is intended to be surface mounted to a printed circuit board of the portable communication device. The connector has a housing and contacts to be soldered to the printed circuit board. The housing has snap-fit lugs and positioning dogs to locate the housing for pressing the contacts on the printed circuit board with coflatness of the contacts before soldering of the contacts to the printed circuit board.

BACKGROUND OF THE INVENTION 
The present invention relates to an input/output connector intended to be 
surface-mounted on a printed circuit board PCB comprising, among other 
things, an insulating housing on whose lateral parts are fixed two 
positioning dogs to be soldered to the PCB, contacts to be soldered to the 
PCB. It also relates to the process for mounting the said connector. 
In a general and known manner, the input/output connector of a portable 
communication device, for example a mobile telephone, which is of very 
small dimensions, is surface-mounted on a printed circuit board PCB. For 
the sake of conciseness and simplification the printed circuit board will 
hereafter be referred to as PCB ("Printed Circuit Board"), the term 
commonly used by those skilled in the art. This connector thus makes it 
possible to connect and disconnect an exterior electronic device, equipped 
with a complementary connector, to the portable communication device so as 
to permit dialogue between the two devices, or the testing of the 
functions or components installed on the PCB. Given the very small size of 
the connector used for this type of application and the vital need for 
highly accurate positioning during the mounting thereof so that the 
bearing plane of the connector coincides or at least almost coincides with 
the plane of the PCB, specific means for positioning and fixing the 
connector as well as the contacts must be provided. Thus, when 
implementing the product, the surface-mounting of the component, and also 
throughout the lifetime of the portable device, sometimes under severe 
handling conditions, all the contacts of the complementary connectors 
should be able to engage with one another and ensure that the contact 
pressure is adequate for good electrical transmission. Thus, it has been 
observed that for this function to be effective, it is necessary for the 
bearing plane of the connector to coincide or at least almost coincide 
with the plane of the PCB. In fact, this coplanarity provides for an 
efficient answer to a requirement for so-called coflatness, necessary for 
the implementation of the surface-mounting process, which requirement 
implies that any contact must be located within a maximum tolerance 
interval, which is desired to be small (for example of the order of 0.1 
mm), in relation to the plane of bearing of the connector on the PCB, 
which bearing plane defines the plane of reference for the said 
coflatness. 
International application WO 96/07221 describes such a connector which uses 
metal soldering fixings intended for holding it and setting it in position 
on the PCB. However, the use of such fixings has a considerable drawback 
since it does not allow the abovementioned necessary accuracy and hence 
the coflatness requirement to be met sufficiently rigorously. This is 
because the fixings described rest on the PCB over the whole of the 
surface of their base whilst, moreover, the connector rests at the rear on 
the said PCB either on a mounting surface or on a set of contacts. Thus, 
three surfaces which are independent and consequently whose probability of 
being coplanar is extremely small, the two surfaces of the bases of the 
fixings and the surface via which the rear of the connector rests on the 
PCB, are in this case involved in determining the plane of bearing of the 
connector on the PCB. Moreover, the dimensional constraints of the product 
do not allow sufficiently accurate guiding of the contacts. All of the 
above implies that this bearing plane evidently cannot be determined in an 
accurate and reproducible manner and yet, as was stated earlier, this 
bearing plane defines the plane of reference for the coflatness of the 
contacts and thus a considerable scatter is created as regards the 
coflatness. 
SUMMARY OF THE INVENTION 
In this context, the object of the present invention is efficiently to 
overcome this considerable drawback exhibited by the prior art and 
proposes an input/output connector whose design makes it possible to 
guarantee that the contacts, during mounting on the PCB, will all lie 
accurately and reproducibly at least in a predetermined tolerance 
interval, the maximum tolerance interval, and that the coflatness 
requirement can thus be satisfied rigorously. 
To do this, the input/output connector mentioned in the preamble is 
noteworthy in that it comprises an elastic means for holding of the 
snap-fit type to the PCB intended, when the said connector is placed on 
the PCB for surface-mounting, to hold the contacts pressing on the said 
PCB, the surface-soldering thus being carried out while each of the 
contacts is in a position such that it is contained in a plane of 
reference for the coflatness of the said contacts. 
In a subsidiary manner, the input/output connector comprises an elastic 
means for holding of the snap-fit type to the PCB intended, when the said 
connector is placed on the PCB for surface-mounting, to hold the contacts 
pressing on the said PCB, the surface-soldering thus being carried out 
while each of the contacts is in a position such that it lies in a 
predetermined tolerance interval with respect to a plane of reference for 
the coflatness of the said contacts. 
In a likewise noteworthy manner, according to the present invention, there 
is provided a process for mounting the input/output connector, in the 
course of which, when the said connector is presented so as to be jammed 
into a housing of the PCB provided for this purpose, the bearing load 
exerted on the connector, in a placement phase during surface-mounting, is 
used to bring about the automatic snap-fitting of the connector to the 
PCB, the assembly thus pressed together being surface-mounted on the PCB 
in the exact desired plane. 
Thus, the invention consists advantageously in designing a connector 
provided with an elastic means of holding which, when placing the 
connector on the PCB, will make it possible to apply pressure and, once 
the snap-fitting has been carried out automatically, to keep the contacts 
constrained on the PCB in a position such that each of the said contacts, 
once immobilized, is contained in a plane of reference for the coflatness 
of the contacts, or at worst, subsidiarily, lies in the predetermined 
maximum tolerance interval with respect to the said plane of reference. 
Thus, in a general manner, in the placement phase (termed "pick and place" 
by those skilled in the art) carried out by a machine for the 
surface-mounting of a component (here a connector), a bearing load of the 
order of 100 to 300 grams is exerted on the components. The technique 
utilized therefore consists in using this load to snap-fit the connector 
to the PCB automatically. The term "of the snap-fit type" should here be 
given its widest expression permitting the choice of means such as: 
fastening pins, snap-fit lug, quick-setting cement spot, etc. This 
technique is accurate, efficient and reproducible and the coflatness 
requirement is thus guaranteed to be complied with in full. Moreover, by 
virtue of the snap-fit means which makes it possible to hold the contacts 
constrained in the desired position, an operation of cementing the said 
contacts is completely obviated, this constituting another considerable 
advantage.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIGS. 1 and 2 will be utilized simultaneously for a proper understanding of 
the characteristics of the connector in accordance with the invention in 
its first embodiment. Represented in perspective in FIG. 1 is a connector 
1 intended to be surface-mounted, that is to say to be soldered according 
to the "surface-mounted components" (termed SMC by those skilled in the 
art) technology, on a printed circuit board PCB which comprises a housing 
H to which the connector 1 is presented (the arrow labelled S in FIG. 1 
specifies the direction of placement) and then jammed fast. The connector 
1 consists chiefly of an insulating body 2, it comprises a set of contacts 
3, a pair of interlocks 4 intended to be soldered to the PCB as well as a 
pair of positioning dogs 5 likewise intended to be soldered to the PCB to 
hold the connector in position on the said PCB. Preferably, the 
positioning dogs 5 are mounted in a removable manner on the body 2 which, 
in order to receive them, has on its two side walls two lugs 6 in the 
shape of an inverted L and under which each positioning dog 5 is slid and 
immobilized. Each positioning dog 5 can comprise, on its flat part 51 
intended to come into contact with the PCB and located towards its end 
situated furthest outboard of the PCB, a projection 52 or boss of small 
height designed to form a point contact with that part of the PCB intended 
to receive it. The two points of contact of the two projections 52 
therefore mathematically determine a straight line support for an axis of 
rotation XX' of the connector allowing it, while it is being mounted, to 
swing in such a way that the contacts 3 are brought close in turn to 
corresponding contact pads of the PCB (which are not shown in the 
drawing). This projection 52 and its characteristics are disclosed in 
detail in a French Patent Application filed on the same date by the same 
applicant, this Patent Application being incorporated herein by way of 
reference. In accordance with the invention the input/output connector is 
noteworthy in that it comprises an elastic means for snap-fit holding the 
housing to the PCB which is intended, when the said connector is placed on 
the PCB for surface-mounting, to hold the contacts pressing on the said 
PCB, the surface-soldering thus being carried out while each of the 
contacts is in a position such that it is contained in a plane of 
reference for the coflatness of the signal contacts, or lies in a 
predetermined tolerance interval with respect to the said plane of 
reference. In the first embodiment of the connector according to FIGS. 1 
and 2, the elastic means for holding of the snap-fit type consists of 
snap-fit lugs 21 (deliberately represented thicker than necessary in the 
drawing so as better to elucidate the possible shape) situated on the 
lateral parts of the insulating housing 2 opposite the positioning dogs 5 
in such a way that the PCB is, once the snap-fitting has been effected at 
the time that the bearing load is exerted on the connector 1 for the 
surface-mounting, held clamped between the said snap-fit lugs 21 and the 
said positioning dogs 5 while the contacts 3 then in contact are 
constrained on the corresponding contact pads of the PCB. 
In the second embodiment depicted in FIGS. 3 and 4, the same labels apply 
to elements identical to those of FIGS. 1 and 2. In this second 
embodiment, the elastic means for holding of the snap-fit type consists of 
at least one snap-fit lug 22 (deliberately represented thicker than 
necessary in the drawing so as better to elucidate the possible shape) 
situated on the rear part of the insulating housing 2 opposite the 
contacts 3 in such a way that the PCB is, once the snap-fitting has been 
effected at the time that the bearing load is exerted on the connector 1 
for surface-mounting, held clamped between the said snap-fit lug 22 and 
the contacts 3 while constrained on the corresponding contact pads of the 
PCB. 
In the third embodiment depicted in FIGS. 5 and 6, the same labels apply to 
elements identical to those of FIGS. 1 and 2. In this third embodiment, 
the elastic means for holding of the snap-fit type consists of snap-fit 
lugs 53 situated directly in line with and to the rear of the positioning 
dogs 5 so that the PCB is held clamped between the said snap-fit lugs 53 
and the contacts 3 while constrained on the corresponding contact pads of 
the PCB. The PCB is furthermore trapped between the snap-fit lugs 53 and 
the interlocks 4. Moreover, in a preferred manner, the extreme parts 530 
of the snap-fit lugs 53 intended to come into contact with the PCB possess 
a cutout 531 and are inclined with respect to the plane orthogonal to the 
plane of the PCB in such a way as to amplify the elastic effect as may be 
seen in FIGS. 5 and 6. Indeed, the inclined geometry of the section 
through these snap-fit lugs 53 makes it possible to maintain pressure on 
the contacts 3 by take-up of play. 
This technique implemented in a non-limiting manner according to the 
various embodiments, whilst offering excellent reproducibility, affords a 
simple and efficient solution to the problem posed by the coflatness 
requirement. Furthermore, as stated earlier, such a technique using 
snap-fit means, owing simply to the fact that it makes it possible to hold 
the contacts constrained in the desired position by altering their 
elasticity, completely obviates any operation of cementing the said 
contacts, an operation ordinarily employed for the connectors of the prior 
art.