Plug-type connector between wiring backplanes and assembly printed circuit boards

The invention is directed to a plug-type connection composed of blade connector and spring clip, whereby the individual contact passages are surrounded by electrically conductive shielding plates that are connected to shield contactings carrying a ground or shield potential. The shield contactings are to an intermediate shielding grid system located both at the backplane side and at the circuit board or module side. In order to achieve an improved interconnect passage width between the contact blades and the shield contactings arranged in the intermediate grid, the electrical connection between the connector or spring clip and assembly printed circuit board ensues on the basis of pressure of spring-like bent terminal ends which flatten onto contact surfaces on the assembly printed circuit board.

BACKGROUND OF THE INVENTION 
The invention is generally directed to a plug-type connection between a 
wiring backplane and an assembly printed circuit board. More particularly, 
the present invention relates to such a connector which is shielded. 
A plug-type connector wherein a shielding ensues in an intermediate 
shielding grid, as recited above, has been disclosed in European Patent 
Application 94 103 192. Such conventional plug-type connector arrangements 
partly present the disadvantage that too small an interconnect passage 
width is established on the printed circuit boards between the contact 
blades and the shield contactings arranged in the intermediate grid. This 
results in the fact that the multilayer requires additional layers and 
thus becomes expensive. 
An object of the present invention is therefore comprised in creating a 
plug-type connection of the species initially cited wherein an adequate 
interconnect passage width is established and that does not require any 
expensive multilayers. 
SUMMARY OF THE INVENTION 
These objects are inventively achieved by providing a plug-type connector 
for conductively connecting a wiring backplane to a printed circuit board. 
The connector includes a plurality of conductive shielding plates arranged 
to form a plurality of receptacle chambers. The shielding plates are 
connectable to a shield voltage. A plurality of contact springs are 
provided such that each contact spring is disposed in one of the 
receptacle chambers and is insulated from the shielding plates. Each 
contact spring has a blade contact end for contacting the backplane and an 
opposite terminal end for contacting the printed circuit board. A 
plurality of shielding plate terminal ends extend from at least some of 
the shielding plates, and these terminal ends are each bent to form a 
prestressed portion or spring projection. In an uninstalled condition of 
the connector, the spring projection terminal ends extend toward the 
printed circuit board in a bent fashion at an angle or bowed curve. 
However, in an installed condition of the connector, the terminal ends are 
contactable against a plurality of corresponding terminal contact surfaces 
disposed on the printed circuit board to which provide shield voltage. The 
connector is mechanically secured against the printed circuit board at a 
plurality of locations so that each terminal end resiliently flattens 
against the corresponding terminal contact surface. 
In an embodiment, terminal extensions of the contact springs are bent to 
form a biased spring projection in a manner similar to the shield plate 
terminal ends. 
Furthermore, according to an embodiment of the invention, the shielding 
plate compartment includes transverse shielding plates arranged 
perpendicularly relative to the assembly printed circuit board which are 
corrugated. Also, portions of the contact spring parts proceeding 
perpendicularly relative to the assembly printed circuit board are 
corrugated. Thus, a continuous predetermined force can be provided against 
terminal eyelet or contact surface of the circuit board. An advantage of 
this plug-type connection is that it can be easily dismantled. 
In the plug-type connector according to the present invention, contacting 
generally occurs on the outside surface of the printed circuit board in a 
surface-mount manner. Thus, the need for a press-in hole is eliminated in 
creating a desired interconnect or lane guidance on the assembly printed 
circuit board. Electrical linking to individual layers of multilayered 
printed circuit board can ensue at any selected location with small 
changers. 
In an embodiment, at the module side, the terminal ends of the shielding 
plate compartment and the terminal ends of the contact springs are bent 
over prior to installation against the surface of the printed circuit 
board or downwardly-extending spring leg or bowed portion. Terminal 
eyelets or contact surfaces are provided on the assembly printed circuit 
board in a counter-region contacting against the terminal ends. The 
terminal ends and the contact surfaces are soldered together. The spring 
clip is mechanically secured on the assembly printed circuit board at a 
plurality of locations. An advantage of this is a better electrical 
connection as a result of the soldering. However, such an embodiment 
requires unsoldering in order to dismantle the connection. 
In an embodiment, the plug-type connector is composed of a blade connector 
fashioned as a rectangular housing open at one side for plugging onto the 
blades of a wiring backplane and of a spring clip that can be plugged into 
the blade connector, provided with receptacle chambers equipped with 
contact springs, and firmly joined to an assembly printed circuit board, 
whereby the blades and springs are arranged parallel in a plurality of 
rows, whereby the individual contact passages are surrounded by 
electrically conductive shielding plates that are connected to contactings 
carrying shield potential that are attached in the intermediate grid both 
at the backplane side as well as at the module side, the contactings being 
grounded or charged with an appropriate shielding voltage.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS 
The present invention provides a connector or spring clip 1 for 
electrically connecting between a wiring backplane 7 and a printed circuit 
board 4. The spring clip 1 includes a shielding plate compartment 2 formed 
of a plurality of shielding plates arranged together to define a plurality 
of receptacle chambers. 
The spring clip 1 also includes conductive contact springs 16, each of 
which provides an electrically conductive connection between a contact on 
the backplane 7 and a corresponding signal contact on the printed circuit 
board 4. Each contact spring 16 typically has a first end shaped to 
receive a contact blade from the wiring backplane 7 and a second end or 
spring contact terminal end which contacts the printed circuit board 4. 
Each spring contact 16 is disposed in one of the receptacle chambers so 
that it is generally surrounded by shielding plates, but insulated 
therefrom. 
The shielding plate compartment 2 of the spring clip 1 includes transverse 
plates 3 when the spring clip 1 is installed against the circuit board 4 
perpendicularly relative to the assembly printed circuit board 4. The 
transverse plates 3 include terminal ends 6. The terminal ends 6 face the 
printed circuit board 4 and are generally extensions of the shielding 
plate; each being bent to form a spring projection. As illustrated in 
FIGS. 3a and 3b, in an uninstalled condition, each terminal end 6 is bent 
away, forming the spring projection or prestressed contact which extends 
at an angle or bowed curve toward the printed circuit board 4. 
FIG. 3c illustrates an installed condition of the connector 1 against the 
printed circuit board 4. Terminal eyelets or shield contact surfaces 5 are 
provided on the assembly printed circuit board 4 in the counter-region of 
the shielding plate terminal ends 6, to receive contact therewith. The 
contact surfaces 5 provide the grounding or shield voltage to the 
shielding plate compartment 2. As illustrated, when the connector 1 is 
pressed toward the printed circuit board 4, the terminal ends 6 each 
flatten against the corresponding contact surface 5 providing a reliable 
shielding contact. The contact surfaces 5 as well as the terminal ends 6 
can comprise upgraded contact surfaces which, for example, can be gold 
plated. A low contact resistance is thereby created. 
The spring clip 1 (not shown here in the installed condition) is firmly 
screwed to the assembly printed circuit board 4 or is connected thereto by 
some other mechanical securing means, such as by a press-in fitting. Such 
a mechanical securing means provides a securing force of the spring clip 
against the printed circuit board which overcomes the contact force of the 
corrugated transverse plates between the terminal ends 6 and the 
respective contact surfaces. 
The contact springs 16 can also be formed with spring projection type 
contact spring terminal ends similar to the shielding plate terminal ends 
of the type illustrated in FIG. 3. Such contact spring terminal ends also 
resiliently flatten in reliable contact against corresponding signal 
contact surfaces on the printed circuit board 4. Such an embodiment is 
described below in connection with FIGS. 2, 4a, 4b and 4c. 
In the embodiment of FIG. 1, the transverse portions of the shielding 
plates 6 and transverse portions of the contact springs 17 are preferably 
corrugated. Such a corrugated configuration, for example, provides 
rigidity to these components. 
Since the contacting occurs against an outside surface of the printed 
circuit board 4, a conventional press-in hole type of connection is no 
longer necessary to form an interconnect or lane guidance. The electrical 
linking to the individual layers of a multilayer circuit board can ensue 
at any desired location with small changers. Given employment of this 
solution, the temperature stressing on the signal contact springs 16, as 
required in the surface mount device (SMD) embodiment set forth below, can 
be avoided. 
The spring clip 1 is also connected to the wiring backplane 7 of a module 
frame via blades 8 and shield contactings 9. 
FIG. 2 shows a spring clip 10 having a shielding plate compartment 11 that 
comprises transverse plates 12 which shield contact springs 17. This 
spring clip 10 is firmly joined to the assembly printed circuit board 13. 
In the embodiment shown in FIG. 2, the connection between the spring clip 
10 and the assembly printed circuit board 13 ensues in SMD technique; as 
illustrated in FIGS. 4a, 4b and 4c, and as explained above wherein the 
contact spring terminal ends may be shaped as rounded (FIG. 4a) or 
straight (FIG. 4b) spring projections to flatten (FIG. 4c) against a 
contact surface on the circuit board 13. Corrugated transverse plates or, 
respectively, corrugated portions of the contact springs 17 therefore need 
not be provided in this embodiment. In this embodiment, too, the spring 
clip 10 is mechanically connected to the assembly printed circuit board 4 
in the installed condition. Whether the embodiment of FIG. 1 or FIG. 2 is 
selected is determined according to whether or not one wishes to avoids 
subjecting the spring clip to thermal loads, or whether dismantling 
without unsoldering would be desirable. 
The terminal ends may be soldered to the respective contact surfaces, as 
shown in FIG. 3c (shield terminal end) and FIG. 4c (signal-carrying 
contact spring) by a solder bead 20 and 21, respectively. 
It should be understood that various changes and modifications to the 
presently preferred embodiments will be apparent to those skilled in the 
art. Such changes and modifications may be made without departing from the 
spirit and scope of the present invention and without diminishing its 
attendant advantages. Therefore, such changes and modifications are 
intended to be covered by the appended claims.