GB2158658A - Plug-in casing for integrated circuits - Google Patents

Abstract

The base (21) of a chamber (16) which receives an integrated circuit module (11) is traversed by contact elements firmly embedded in the base (21). The ends of the said contact elements facing the chamber from sockets each adapted to make electrical contact with a connection of the module (11), while the ends remote from the chamber (16) are constructed as plug pins (24). To ensure trouble-free contact between the connections (13) of the module (11) and the contact elements and on the other hand to protect the projecting plug pins (24) from mechanical damage and/or contamination, the ends of the contact elements (22) facing the chamber (16) are constructed in the form of sockets (23), while the bottom (21) is provided on its side remote from the chamber (16) with an apron (29) which surrounds the plug pins (24) and the height of which corresponds at least to the exposed length of the plug pins (24). <IMAGE>

Description

SPECIFICATION Piug-in casing for integrated circuits The invention relates to a plug-in casing for receiving an integrated circuit module.

More particularly the invention relates to a plugin casing for interchangeably holding an integrated circuit module, comprising a chamber for receiving the circuit module having a base which supports the module and is traversed by contact elements which are firmly embedded in the base, the ends of the contact elements facing the chamber being adapted to make electrical contact with each of the connections of the circuit module and the ends remote from the chamber being in the form of plug pins and projecting perpendicularly from the base.

As is known, integrated circuit modules (IC's) have in recent years had their dimensions increasingly reduced and have been provided with an increasing number of connections (legs). Accordingly these connections also have smaller dimensions, with the result that when IC's of this type are handled there arises the not inconsiderable risk of deforming or even breaking off one or other connection of the IC, which would render the IC unusable despite an intact active circuit portion. In these cases it is said that the IC has "weak legs".

There are now complex circuit arrangements, e.g. process control plants, in which interchangeable IC's, for example read-only memories, programmable read-only memories and eraseable programmable read-only memories (ROMs, PROMs and EPROMs) are provided at specific points.

In order to provide better protection for such comparatively fragile IC's during dispatch and also during interdepartmental storage and to facilitate their handling in these cases even by relatively inexperienced personnel, plug-in casings of the type described above are known. A known casing of this type is described for example in DE-OS-24 23 623. The known casing comprises a chamber the depth of which exceeds the thickness of the IC by only a slight degree. The contact elements firmly embedded in the bottom of the chamber and passing through the latter are in the shape of approximately hemispherical rivet heads on their ends facing the chamber. When the IC is inserted it is pressed on to the bottom of the chamber by a bar engaging in opposite walls of the chamber.On both sides of the bar are integrally formed laterally spaced, resilient fingers which are arranged thereon in the manner of a comb and each of which is associated with one of the connections of the inserted IC and is adapted to press the said connection on to the point of the head of the contact element. Since manufacturing tolerances cannot be avoided in the case of the IC and the casing and also in the case of the bar with its resilient fingers, a secure contact between the IC and the heads of the contact elements cannot be ensured with absolute certainty.

The ends of the contact elements remote from the chamber of the known casing are constructed in the form of plug pins projecting at right angles from the bottom of the chamber, no protection being provided for these plug pins. Although these plug pins are dimensioned in such a way that they have a higher degree of mechanical strength than the connections of the IC, in the case of the known casing the said plug pins are nevertheless subjected to mechanical damage and in particular to contamination during handling, so that once again a trouble-free contact between the plug pin and an associated socket in a socket base is jeopardized.

Given this state of the art it is an aim of the invention to provide a casing of the type described and in which in addition to trouble-free protection of the IC there may be trouble-free contact between the connections thereof and the contact elements as well as maximum protection of the plug pins of the contact elements from mechanical damage and contamination.

The present invention provides a plug-in casing for interchangeably holding an integrated circuit module, comprising a chamber for receiving the circuit module having a base which supports the module and is traversed by contact elements which are firmly embedded in the base, the ends of the contact elements facing the chamber being adapted to make electrical contact with each of the connections of the circuit module and the ends remote from the chamber being in the form of plug pins and projecting perpendicularly from the base, characterized in that the ends of the contact elements facing the chamber are in the form of contact sockets, and the base is provided on its side remote from the chamber with a projecting apron which surrounds the plug pins and the height of which corresponds at least to the exposed length of the plug pins.

Preferred features of the invention are set forth in the accompanying dependent claims.

The invention will be further described by way of example with reference to the accompanying drawings, in which: Figure 1 is a perspective exploded view of a casing according to the invention, showing a chamber, an IC module to be associated with the casing and a cover for the chamber, the side facing the chamber being visible therefrom; Figure 2 is a perspective view of the casing of Fig. 1 from underneath; and Figure 3 is an enlarged sectional view through part of the bottom of the chamber, along a plane lying along a row of inserted contact elem#its.

The casing 10 shown by way of Ps ample in the drawing is adapted to receive an IC module 11 with a support member 12 in the form of a flat board, in which the connections ("legs") are secured to the support member 12 in two rows arranged on opposite longitudinal sides of the board and project at right angles from and towards the same side of the support member 12. The casing 10 is adapted to be plugged into a socket base, for example as described in US-A-3,763,459. It is to be understood, however, that the casing will be adapted accordingly in each case to the IC to be used and/or to the socket base provided.

In the present case the casing 10 comprises a casing body 14 and a cover 15. In the casing body 14 is formed a chamber 16 which is defined by end walls 17,18 opposite one another and longitudinal walls 19,20 opposite one another and by a flat bottom 21. As evident from Fig.3, the bottom 21 is traversed by contact elements 22 which are firmly embedded therein and are arranged in two rows corresponding to the rows of the legs 13 of the IC.

The end of each contact element 22 facing the chamber 16 is in the form of a socket 23, the open end of which is in alignment with the inside surface of the bottom 21 of the chamber 16. The end of each contact element 22 remote from the chamber 16 is in the form of a plug pin 24 (cf. also Fig.

2). The sockets 23 are used, as shown in Fig. 3, for receiving the connections 13 of the IC module 11, while the plug pins 24 are to be plugged into a socket base (not shown).

In the bottom 21 are provided two through openings 25 which are used to press out an IC module 11, which has been inserted with its connections 13 into the sockets 23 in the direction of the arrow 26 shown with broken lines, with a suitable tool (not shown), keeping the connections and sockets parallel to prevent bending of the connections 13.

Fig. 2 shows that the bottom 21 is reinforced on its side remote from the chamber 16 by longitudinal ribs 27 and transverse ribs 28 integrally formed thereon. The plug pins 24 are embedded in the longitudinal ribs 27 so that in addition to the reinforcing function, the longitudinal ribs 27 also contribute towards increasing amount of material surrounding and supporting the contact elements 22.

Fig. 2 also shows that the outer side of the bottom 21, remote from the chamber 16, and therefore also the rows of plug pins 24 are surrounded by an apron 29, the wall portions of which are in alignment with the end walls 17,18 and the lateral walls 19,20 respectively of the chamber 16, so that the entire casing body 16 comprises a continuous surface, conveniently in the form of a cube with rounded edges. The height of the apron 29 exceeds the projecting length of the plug pins 24. In addition, the apron 29 is dimensioned such that its free edges surround the body of the socket base (not shown), when the casing 10 containing the IC module 11 has been placed thereon.

It is important that the IC module 11, which in this case is symmetrical to its longitudinal median plsne,should be inserted into the casing 10 in the correct position (and not turned through 1800 for example). The support member 12 of the module 11 is therefore provided with a positioning mark in the form of a notch 30. 1f?ls notch 30 corresponds to a semi-circular hole 31 in the bottom 21 of the chamber. The IC module 11 can then be inserted correctly into the casing 10 when the notch 30 and the hole 31 are in alignment with one another or are at least on the same side.

It is also important for the casing 10 provided with the IC module 11 to be plugged in on the associated socket base in the correct position. As already mentioned, the casing 10 shown is adapted for positioning on a socket in accordance with US A-3,763,459 for example.

This socket base is provided with a pivot lever which can be pivoted from an upright position into a position aligned with the plane of the socket base. Only when the lever is in the upright position are the sockets in the socket base free to receive plug pins. If the pivot lever is swung down against the latter, the sockets are locked in the socket base or the plug pins already inserted therein are blocked. Therefore, before the casing 10 is plugged in on the respective socket base, its pivot lever mentioned above must be raised into the upright position. In this position the pivot lever also acts as a positioning element. In order to receive the pivot lever of the socket base which is in the upright position, there is formed in the casing 10 a recess 32 which extends over its entire height and which also has an extension designated 32' in the cover 15.This recess 32 or 32', together with the raised pivot lever of the socket base, fulfils the function of a positioning element corresponding one-to-one, so that it is quite impossible to plug in the casing 10 on the socket base in a position turned through 1800, i.e. in an incorrect position.

The casing 10 also comprises the cover 35, which is shown from underneath in Fig. 1. The cover 15 comprises a covering wall 33, on the periphery of which is formed the recess 32' already mentioned which corresponds to the recess 32. An apron 34, which, when the cover is placed on the casing body 14 comes to rest on the insides of the end walls 17,18 and the lateral walls 19,20 of the chamber 16, is integrally formed on the covering wall 33. In the centre of the two longitudinal sides of the apron 34 are integrally formed resilient locking catches 35 which cooperate with catching lugs 36 integrally formed on the lateral walls 19,20, there additionally being provided through openings 37 in the bottom 21 of the chamber 16 at the level of the catching lugs 36 to permit passage of the free ends of the locking catches 35.In order to lift the cover 15 from the casing body 14 once it has been plugged in and locked, a notch 38, through which for example the blade of a screwdriver can be inserted and thus permit the cover to be lifted away, is provided in the end wall 18.

The cover 15 placed on the casing body 16 is used not only to protect the IC module 11 from mechanical damage and/or from dirt, but also to protect them from radiation, for, as is known, there are eraseable programmable read-only memories (EPROMs), the memory content of which, once input, can be erased by intensive UV radiation. The cover 15 and the casing body 14 are therefore preferably produced from a light-impermeable plastics material.

Finally, Fig. 1 indicates that on the lateral wall 19 (and/or on the lateral wall 20 or on one of the end walls 18,19 respectively) an adequate area is available for marking space 39 (whether by direct marking or by labelling) on account of the fact that the corresponding portions of the apron 29 are in alignment with the said walls of the chamber, so that the casing provided with the IC module 11 can not only be clearly designated, but it also offers excellent protection for the IC module from damage and for the plug pins 24 from damage and dirt during storage, during replacement, during dispatch and during handling generally by unskilled personnel.

Claims (9)

1. A plug-in casing for interchangeably holding an integrated circuit module, comprising a chamber for receiving the circuit module having a base which supports the module and is traversed by contact elements which are firmly embedded in the base, the ends of the contact elements facing the chamber being adapted to make electrical contact with each of the connections of the circuit module and the ends remote from the chamber being in the form of plug pins and projecting perpendicularly from the base, characterized in that the ends of the contact elements facing the chamber are in the form of contact sockets, and the base is provided on its side remote from the chamber with a projecting apron which surrounds the plug pins and the height of which corresponds at least to the exposed length of the plug pins.

2. A casing as claimed in claim 1, characterized in that the upper ends of the contact sockets are aligned with the surface of the base facing the chamber.

3. A casing as claimed in claim 1 or 2, characterized in that the apron is in alignment with end and side walls of the chamber.

4. A casing as claimed in any one of claims 1 to 3, characterized in that the base of the chamber is provided with positioning markings which correspond to positioning markings on the integrated circuit module to enable insertion of the module with its connections into the contact sockets in a predetermined relative position.

5. A casing as claimed in any one of claims 1 to 4, characterized in that the base of the chamber is provided with openings which are usable for pressing a plugged-in circuit module out of the contact sockets from the side of the base remote from the chamber.

6. A casing as claimed in any one of claims 1 to 5, characterized in that a markable area is provided on at least one of the outer faces thereof.

7. A casing as claimed in any one of claims 1 to 6, characterized in that a removable cover is provided for closing the chamber.

8. A casing as claimed in any one of claims 1 to 7, which is adapted to be placed on a socket base provided with a positioning member, characterized in that a positioning element shaped to match the positioning member of the socket base is formed on the casing.

9. A plug-in casing for removably holding an integrated circuit, substantially as hereinbefore described with reference to the accompanying drawings.