GB2239565A

GB2239565A - An electrical plug-in connection device for circuit boards

Info

Publication number: GB2239565A
Application number: GB9025980A
Authority: GB
Inventors: Gerhard Pirner
Original assignee: Messerschmitt Bolkow Blohm AG
Current assignee: Airbus Defence and Space GmbH
Priority date: 1989-12-02
Filing date: 1990-11-29
Publication date: 1991-07-03
Also published as: FR2655483A1; DE3939936A1; GB9025980D0

Abstract

To facilitate connection and disconnection of a plurality of contacts without a large force being required, sockets (7), inside casing (2), having springy contact lugs (10) which can be pressed against pins (8') when inserted into the sockets, are controlled by way of a common clamping element (13). The sockets (7) are themselves connected to pins (8) of the same device, which protrude from the casing, so that several circuit boards can easily be electrically and mechanically interconnected by stacking. <IMAGE>

Description

AN ELECTRICAL PLUG-IN CONNECTION DEVICE FOR CIRCUIT BOARDS This invention

relates to an electrical plug-in connection device for circuit boards.

German specification DE-OS 36 14 689 descr.ibes an arrangement of pins which are in advantageous positions on the bottom sides of circuit boards with corresponding sockets on the top sides. This arrangement of pins and sockets allows the stacking of circuit boards so that they are mechanically and electrically connected to one another. The sockets have springy contact lugs, so that the pins are tightly held when inserted, ensuring adequate electrical contact. However, an electrical plug-in connection device of this type uses only a few contacts since using many contacts would have two main disadvantages:

the geometrical arrangement of the pins and the sockets would need to be extremely precise; and 2) a considerable mechanical resistance would result due to the springy contact lugs which need to be overcome when inserting the pins into the sockets.

A plug-in connection device of this type is thus only suitable for an arrangement of circuit boards needing only a few electrical interconnections between each board.

However, circuit boards with micro-electronic circuits, for example, processor or logic circuits, require a considerable number of such plugin connection devices to interconnect the boards, and these connections are usually made by a so-called bus system. This system, which is a multicircuit system on the circuit board, is connected on the one side to a plug with a plurality of regularly arranged pins, and on the other side to a socket with a corresponding number of apertures SJL281190 2 - which accommodate the pins of the plug. Plug-in connection devices of this type also include springy contact lugs in the sockets which hold the device mechanically secure to ensure a good contact.

A noticeable force is required both to connect and disconnect these devices and for this reason alone, they can only include a limited number of pins or sockets, at the most a few hundreds. Although this number is sufficient for the interconnection of circuit boards with electronic circuits having 16-bit or 32-bit data buses, such connectors will no longer be adequate to meet the expected development of microprocessors which may include data bus systems of 64, 128 or more bits. Thus, rigidly arranged systems will then be required and the dimensions and costs will be considerably higher-than those of conventional, lower bit, systems. Moreover, when this cost is added to the expense of the mother boards of such high-pole bus systems, the total cost would be very gre at relative to the electrical functions they would offer.

Separate write and read data buses, as well as differential data transmission, are desirable in order to avoid interference during data transfer but both require an increase in the number of pins of the plugin connection devices and can thus not be applied by conventional techniques.

So-called test sockets are known which have on the top side of a casing a plurality of sockets into which the pins of a plug can be inserted without force. These sockets then clamp the pins via a clamping element. These test sockets are used, for example, for testing the functional capabilities of electronic assemblies having many pins. However, these test sockets have no pins connected to them and are'thus unsuitable for the connection of circuit boards.

SJL281190 3 - It is an object of the present invention to provide an electrical plug-in connection device of a type which permits the electrical interconnection of circuit boards which have a plurality of connections yet can be of a simple and miniature construction.

According to the present invention an electrical plug-in connection device for circuit boards comprises a casing with a bottom plate into which pins are inserted and from which they protrude, sockets, connected to the pins and arranged inside the casing, said sockets having an open cross-section which is at least as large as the cross-section of the pins, and a common locking element for all sockets, which, in a first position reduces this cross-section for the purpose of clamping other pins which have been inserted into the sockets.

Accordingly, the electrical plug-in connection device is arranged as a socalled zero-force device wherein the socket is arranged to allow the pins to be inserted without force and then clamped in place by a common clamping element.

A plug-in connection device according to the present invention permits several hundreds of interconnections between circuit boards thereby permitting use of these electrical plug-in connection devices with circuit boards which include processor circuits with high-pole circuit systems.

The plug-in connection device of the invention can be mounted directly onto a circuit board, for example, by insertion into an aperture therein, and can thereby provide both a bus plug and a bus system termination.

Preferably, the plug-in connection device is a miniature construction even with a plurality of pins and sockets.

SJL281190 4 - Preferred embodiments can accommodate, for example, 361 pins and sockets in an area of approximately 35 CM2. It is also possible to mount several of these plug-in connection devices onto one circuit board due to their compactness. Other possibilities include use, for example, as separate write and read data buses and changeover to differential data transfer.

The plug-in connection device of the invention also allows construction of bus systems without mother boards which are suitable for highoutput computers, for example, 64-bit-data buses. These systems are low in weight and can simultaneously be used as mechanical connections to several circuit boards. Production costs are also reduced due to dispensing with the mother boards. Plug-in connection devices of the invention, whether used as a bus system or input-output plugs, also require less board surface than other high-pole connecting strips. Maintenance work is also made easier, as the plug connections can be disconnected and reconnected any number of times; even the exchange of individual boards is quite possible.

A specific embodiment of the invention will now be described, by way of example with reference to the accompanying drawings, in which:

Fig. 1 is a partial cross-sectional side view of a plug-in connection device according to the invention; Fig. 2 is a fragmentary schematic illustration of the plug-in connection device during insertion of a pin into a socket; Fig. 3 is a schematic illustration of the device showing a pin clamped into a socket by a clamping element; Fig. 4 is a view from above of a part of the clamping element; 1 SJL281190 Fig. 5 is a view of a plug-in connection device according to the invention, mounted on a circuit board; and Fig. 6 is a side view of several stacked circuit boards interconnected by means of plug-in connections devices according to the invention.

A plug-in connection device 1 as shown in Fig. 1 comprises a casing 2 in the form of a flat box including a bottom plate 3, a cover plate 4 and lateral walls 5, which enclose an inner hollow space 6. The contact elements each consist of a socket 7 and a pin 8-connected thereto, with the pins 8 extending through the bottom plate 3 and the socket openings facing towards the cover plate 4. Referring to Fig. 2, other pins 81 can be inserted into these sockets 7 via openings 9 in the cover plate 4.

As schematically illustrated in Figs. 2 and 3, each socket 7 has a springy contact lug 10 and a fixed contact lug 11. The fixed contact lug 11 may be supported by support elements 12, which provide, for example, sub-divisions of the hollow space 6, as shown in Fig. 3. The sockets 7 are provided with a clamping plate 13 which has evenly spaced openings 14, corresponding in position to the openings of the sockets 7 and fitting around the said sockets 7. This clamping plate 13 is guided within the casing along the lateral walls 5 and can be displaced in the casing 2 as is indicated by arrows in Fig. 2 and 3. This can be achieved, for example, by using a spindle drive 15, as indicated in Fig. 3. This spindle drive 15 comprises a spindle 16 which is mounted at one end in a lateral wall 5 of the casing 2, and, at the other end, with the casing, in a spindle socket 17. The spindle 15 can be adjusted from the outside by way of a screw head 18. A spindle nut 19, which is connected, for example, via a bolt 20 to the clamping plate 13, moves along this spindl e 16.

SJL281190 When the clamping plate 13 is moved fully to the left, as shown in Fig. 2, the sockets 7 each have an open crosssection which is larger than the cross-section of those pins 8' which are to be inserted into the sockets. Thus, the pins 81 can be pushed into the sockets 7 without force. When this has been done, the clamping plate 13 is pulled towards the right by way of turning spindle 16, as shown in Fig. 3, so that the springy contact lugs 10 are pushed along by the edges defining the openings 14 and pressed against the pins 8', thus clamping the latter in sockets 7. If the pins 81 are to be removed from the sockets 7, the clamping plate 13 is pushed towards the left by turning the screwhead 15 in the opposite direction, thereby permitting removal of the pins 81 without force.

In Fig. 5, a plug-in connection device 1 of the type described above is mounted on a circuit board 21 by insertion of the pins 8 through openings not (not shown) in the board 21. Several semi-conductor circuits 22, for example, several chips of a processor, and other assembly elements, which are only partially shown, are also mounted in the board 21 as illustratect in Fig. 5. Electrical connection of the pins 8 to the circuit board can be made, for example, by soldering.

In Fig. 6, several circuit boards 21 of this type are stacked and are mechanically and electrically connected to one another by means of plugin connection devices 1, which are inserted into the circuit boards, as just described. A multiple plug 23 can be inserted into the sockets of the plug-in connection device on the uppermost circuit board, to establish, for example, the connection to a testing system or another circuit. On the left side in Fig. 6 another connection device 1', without pins, is shown and this may serve, for example, to accommodate a multiple plug 24 of an input-output circuit.

A 1 SJL281190 Although the illustrated embodiment of the plug-in connection device is described as being directly connected to a circuit board 21 in Figs. 5 and 6, it is of course possible to use the device as a unit independent of the circuit board, by connecting the circuit board to the device via a cable.

Furthermore, although the plug-in connection device is shown mounted approximately centrally of the circuit board, 21, this is merely an example, and other arrangements such as mounting the device at the edge of the board or using different orientations of the pins are possible.

1 SJL281190

Claims

1. An electrical plug-in connection device for circuit boards comprising a casing with a bottom plate into which pins are inserted and from which they protrude, sockets, connected to the pins and arranged inside the casing, said sockets having an open cross-section which is at least as large as the cross-section of the pins, and a common locking element for all sockets, which, in a first position reduces this cross-section for the purpose of clamping other pins which have been inserted into the sockets.

2. A connection device as claimed in claim 1 wherein the sockets have at least one springy contact lug against which the locking element acts to reduce the cross-section of the sockets.

3. A connection device as claimed in claim 1 or 2 wherein the locking element is a locking plate with regularly arranged openings which embrace the sockets, and means is provided in the casing for displacement of the locking plate.

4. A connection device as claimed in claim 3 wherein the means for displacement of the locking plate is a spindle drive.

5. A connection device as claimed in any preceding claim when directly connected to a circuit board.

6. A connection device as claimed in claim 5 inserted into an opening of the circuit board, such that the openings of the sockets lie above or in the vicinity of the top surface of the circuit board in a plane parallel to the plane of the circuit board and the pins protrude from the bottom surface of the circuit board so that they can engage into sockets of another similar connection device which is connected to a 1 f ' SJL281190 - 9 - further circuit board.

7. An electrical plug-in connection device for circuit boards substantially as hereinbefore described with reference to and as illustrated in Figs. 1 to 4 of the accompanying drawings.

Publishedd 1991 at The Patent Office. State House. 66171 High Holborn. LondonWC I R 47P. Further copies may be obtained from Sales Branch, Unit 6. Nine Mile Point, ewmfcbnfach, Cross Keys, Newport NPI 7HZ. Printed by Multiplex techniques lid. St Mary Cray. Kent.