GB2040604A - Mounting a DIP on a circuit board - Google Patents

Abstract

An electrical connector for removably connecting a DIP 66 to a circuit board 16 includes a socket 10 and mating DIP carrier 12 in which the socket includes a plurality of contacts 36 disposed along two sides thereof with the terminal portion of each contact extending through the bottom of the socket and the contact portion extending through the side wall and into a carrier-receiving inner receptacle 14 formed in the top of the body. Each end of the socket is provided with keyways 22, 24 and 26. The carrier body is receivable within the socket receptacle 14 and is adapted to receive a DIP 66 in inverted disposition in the bottom thereof. The carrier 12 includes vertical slots formed in each side for receiving the DIP legs in recessed disposition, and a longitudinally extending beam 68 which forms a detent for locking the carrier 12 within the socket 10. The ends of the carrier 12 are keyed 50, 52 and 54, 56 to match the socket keyways and a pull tab 88 is formed on the upper side of the carrier body for facilitating insertion and removal of the carrier into and out of the socket. When the carrier 12 is inserted into the socket 10, the socket contacts 36 are received within the side slots of the carrier and engage the DIP legs. <IMAGE>

Description

SPECIFICATION Mounting a DIP on a circuit board This invention relates generally to integrated circuit component connector apparatus and more particularly to an improved carrier and socket device for facilitating the connection and disconnection of DIP packaged integrated circuits in electronic apparatus.

Heretofore, integrated circuit components packaged in duel in-line packages (DIPs) have been either soldered directly to a printed circuit board or have been mounted on a multi-pronged carrier which is in turn plugged into a fixture on a circuit board. Although such connection is suitable for certain applications, it is not suitable for those applications in which static discharge presents a problem relative to the integrity of the packaged integrated circuit. For example, in circuits such as ROM devices, static charge transferred from the fingers of one picking up the device to the conductive legs thereof is capable of destroying either the device or the data stored therein, or perhaps even both.

Whereas a DIP permanently soldered to a circuit board is not normally susceptable to static discharge problems, it is not readily removable from the board for testing or replacement. On the other hand, whereas a DIP mounted to a standard plugable carrier is readily removable from the supporting circuit board, it is not free from static discharge problems because the plugable prongs to which it is connected are exposed to the touch of the one holding the carrier.

It is therefore a principal object of the present invention to provide a novel socket and removable DIP carrier which protects the DIP from static discharge during handling.

Another object of the present invention is to provide a socket for attachment to a circuit board and a mating DIP carrier which is adapted to be readily insertable and removable from the socket.

Accordingly, the present invention provides apparatus for removably connecting a duel in-line packaged electrical component (DIP) to a circuit board, comprising: socket means, including a first body having a carrier receiving cavity formed therein, and a plurality of contact means disposed in spaced-apart relationship along opposite sides of said carrier receiving cavity, each of said contact means having a resilient end portion extending into said cavity and an opposite end portion extending through said first body for attachment to said circuit board; and carrier means including a second body having a first portion with an external configuration dimensioned so as to be matingly receivable within said carrier receiving cavity, a DIP-receiving cavity formed within said first portion, a plurality of openings formed along opposite sides of said first portion and providing passageways through which said resilient end portions of said contact means respectively extend to contactingly engage the conductive legs of a DIP contained in said DIPreceiving cavity when said first portion is disposed in said carrier-receiving cavity, and a second portion forming means for facilitating the separation of said carrier means from said socket means.

A preferred embodiment of the present invention includes a generally rectangular socket and mating DIP carrier in which the socket component includes a plurality of contacts disposed along two sides thereof which the terminal portion of each contact extending through the bottom of the socket and the contact portion extending through the side wall and into a carrier-receiving inner receptacle formed in the top of the body. Each end of the socket is provided with keyways. The external perimeter of the carrier body is configured to be matingly received within the socket receptacle and is adapted to receive a DIP in inverted disposition in the bottom thereof.

The carrier includes vertical slots formed in each side for receiving the DIP legs in recessed disposition, and a longitudinally extending beam which forms a detent for locking the carrier within the socket. The ends of the carrier are keyed to match the socket keyways and a pull tab is formed on the upper side of the carrier body for facilitating insertion and removal of the carrier into and out of the socket. When the carrier is inserted into the socket, the socket contacts are received within the side slots of the carrier and engage the DIP legs.

Among the many advantages of the present invention are that it provides a means for making a DIP readily interchangeable in a functional circuit.

Another advantage of the present invention is that it enables a DIP to be readily removed for testing or substitution.

Still another advantage of the present invention is that the carrier protects the DIP leads from contact with the fingers of a holder and therefore isolates the contained integrated circuit from static charge.

In order that the invention may be readily understood, an embodiment thereof will now be described, by way of example, with reference to the accompanying drawings, in which: FIGURE 1 is an exploded perspective view showing a socket and DIP carrier embodying the present invention; FIGURE 2 is a side elevation of a DIP carrier broken along the line 2-2 shown in Figure 1; FIGURE 3 is a cross-sectional view of the DIP carrier taken along the lines 3-3 of Figures 1 and 2; FIGURE 4 is a side elevational view of the socket broken away along the line 44 as shown in Figure 1; FIGURE 5 is a cross-sectional view of the socket taken along the lines 5-5 of Figures 1 and 4; and FIGURE 6 is a broken segment of a bottom plan view of the socket shown in Figures 1, 4 and 5.

Referring now to Figure 1 of the drawing, there is shown a socket 10 and a mating DIP carrier 12 with the carrier 12 being positioned in exploded relationship above the mating receptacle 14 formed in the top of socket 10. For purposes of illustration, socket 10 is shown disposed above a printed circuit board 16 onto which it is to be mounted.

Referring now additionally to Figures4 and 5, it will be noted that socket 10 is generally rectangular in configuration with the exception that the end wall 1 8 has an offset 20 for accommodating a pair of keyways 22 and 24. At the opposite end of socket 10, a pair of laterallyextending keyways 26, one of which is not shown, are also provided. The side walls 28 and 30 are provided with exterior slots 32 and intersecting interior slots 34 which receive contact members 36 as shown in Figure 5. As indicated in the broken segment of a bottom plan view shown in Figure 6, the contact receiving slots 34 are Tshaped in cross-sectional configuration.Contact members 36 are of conventional configuration and include tapered lower extremities for engaging PC board apertures 17, a widened upper section, illustrated by the dashed lines 38 in Figure 4, and a cantilevered spring contact arm 40 which after insertion into the slot extends into the cavity 14.

The widened portion 38 includes a resilient lock tab 42 which springs into the slot 32 as a member 36 is pushed into slot 34 from the bottom and serves to lock the member 36 in place.

The bottom surface of socket 10 is flat except for integrally formed transverse ribs 33 which extend thereacross to strengthen the socket structure. In addition, the ribs 33 serve as standoffs for raising the main body of the socket above the board surface to which the device is mounted. The inside surface of the socket bottom is plain except for an arrowhead 35b which is molded therein as an alignment reminder. An identical arrowhead 35a is molded into the carrier 12.

Carrier 12 is also generally rectangular in external configuration except that at one end it is provided with protruding key projections 50 and 52 which are adapted to mate with the keyways 22 and 24, respectively, of socket 10, and at the other end it is provided with laterally extending key projections 54 and 56 which mate with the keyways 26 at the corresponding end of socket 10. As illustrated in Figures 2 and 3, the bottom of carrier 12 is provided with a rectangular cavity 57 defined by the interior side walls 58, end walls 60 and the bottom surface 62 of a web 64 that extends along the length of the carrier. The purpose of the cavity is to provide a chamber for receiving the body of a DIP 66 as shown by the dashed lines in Figures 2 and 3.

The sides of the carrier 12 are configured to include a detent beam 68 which extends along the length of each side wall, and a plurality of upstanding posts or ribs 70. The ribs 70 are narrow and shallow from beam 68 to the junction of web 64 so as to provide wide openings 74 (Figure 2) for receiving the knee portion of the DIP legs 76, but are wider and deeper above web 64 so as to provide narrow slots 72 for receiving the tips of the DIP legs as indicated at 78 (Figures 2 and 3).

As indicated in Figures 3, the junction of web 64 with the ribs 70 is made with an upward flare so that the edge portion provides a camming surface 80 for guiding the DIP legs into the slots 72 as the DIP body is inserted into the chamber 57. The upper extremity of the flared portion 82 also provides a shoulder over which the extremity 78 of the DIP legs may be formed to both secure the DIP in the carrier and cause a flat side contact surface to be presented within the slots 72 and 74.

Formed in the central portion of web 64 is a pull tab 83 having flanges 84 on either end to provide a gripping surface with which the carrier may be held between the thumb and index finger of a user. In order to provide additional clearance for the thumb and index finger, apertures 86 are provided in the web 64 on each side of the pull tab 83. The centre of pull tab 83 is recessed both top and bottom to provide a thin web 88 having a rectangular aperture 90 formed therein. The aperture 90 provides entry way for an auxiliary lifting tool (not shown). In order to use such tool, which might, for example, have an inverted Tshaped lower extremity, the T-shaped portion would be inserted through slot 90 and the tool rotated so as to engage the lower surfaces 92 of web 88 and thereby allow carrier 12 to be lifted out of engagement with socket 10.

Note by comparing Figure 2 with Figure 4 that the slots 72 and 74 of carrier 12 are aligned with the contacts 36 in socket 10, and by comparing Figure 3 with Figure 5 that the contact arms 40 extend into the path taken by carrier 12 as it mates with socket 10. This of course, means that, as the carrier is inserted into the cavity 14, the arms 40 will cam over the beams 68 and spring into slots 74 to engage the DIP legs 76. In Figure 5, a partially broken carrier 12 is shown in phantomlines in mating reiationship with socket 10 so as to illustrate the manner in which the contacts 40 engage the legs of the DIP 66.

The beam 68 also provides a detent that cooperates with contact arms 40 to maintain the carrier locked in engagement with the socket.

The spring force of contact arms 40 is selected so that approximately three pounds of withdrawl force must be applied to tab 83 before the carrier will separate from the socket. This also ensures that adequate contact engaging force is applied between arms 40 and DIP legs 76.

In the preferred embodiment the carrier 12 is molded of a glass and carbon-filled polymeric thermo-plastic or thermo-set material such as nylon or polypropylene material having approximately 105 ohms/cm2 of surface resistivity.

By using such material static charge will be dissipated by the material without damaging the integrated circuit contained in the DIP but will provide adequate insulation between the DIP legs.

The carrier 12 is a monolithically molded unit and, with the exception of the contact pins 40, so is the socket 10. The only manufacturing step required in completing socket 10 after it is molded is to insert the contact pins 40 into the openings 34 provided in the bottom surface.

In use, the socket 10 is mounted to a printed circuit board 16 or the like by inserting the contact pins 36 into openings 17 as illustrated in Figure 1 and appropriately soldering the pins to leads formed on the lower side of the board. Socket 10 will rest directly upon the surface of the board but will be slightly separated therefrom by the ribs 33.

It will be appreciated that once the pins 36 are securely soldered to the underside of the board 16, socket 10 will be rigidly secured thereto.

Insofar as the carrier is concerned, any desired type of integrated circuit (e.g., computer chip, ROM, RAM or otherwise) which is packaged in a standard DIP package may be inserted into the carrier by simply inserting the DIP "legs up" into the cavity of the bottom of the carrier. As the legs 76 engage surface 80, they will be guided into slots 72 as the base of the DIP bottoms out against the underside of web 64. The legs are then deformed around the shoulder 82 and the mounting is complete, and the device is ready to be plugged into a socket.

It is important to note that since the width of the slots 74 is small (typically about 1.78 mm) and the DIP legs are recessed within the slots, one holding the carrier in his hand will not touch the DIP legs even if he should improperly grip the carrier. And even if he were to squeeze the carrier hard enough to cause his skin to touch the DIP legs, any difference in static charge between that of his body and the carrier will have already been dissipated by the semiconductive carrier material.

Use of the present invention makes it possible to easily change the electronic functional or storage capability of any modern electronic device. Furthermore, it makes the removal for testing of a particular circuit component quite simple. And since the volume of space required to accommodate the socket and carrier is only slightly larger than that required by the DIP itself, the device has nearly universal application.

Claims (8)

1. Apparatus for removably connecting a duel in-line packaged electrical component (DIP) to a circuit board, comprising: socket means, including a first body having a carrier receiving cavity formed therein, and a plurality of contact means disposed in spaced-apart relationship along opposite sides of said carrier receiving cavity, each of said contact means having a resilient end portion extending into said cavity and an opposite end portion extending through said first body for attachment to said circuit board; and carrier means including a second body having a first portion with an external configuration dimensioned so as to be matingly receivable within said carrier receiving cavity, a DIP-receiving cavity formed within said first portion, a plurality of openings formed along opposite sides of said first portion and providing passageways through which said resilient end portions of said contact means respectively extend to contactingly engage the conductive legs of a DIP contained in said DIPreceiving cavity, when said first portion is disposed in said carrier-receiving cavity, and a second portion forming means for facilitating the separation of said carrier means from said socket means.

2. Apparatus according to claim 1 wherein said first body is made of a semiconductive plastics material.

3. Apparatus according to claim 1 or 2 wherein said openings are in the form of elongated slots extending parallel to adjacent slots and wherein forming means are recessed within said slots about which the conductive legs of a DIP may be formed.

4. Apparatus according to any one of claims 1 to 3 wherein the perimeter of said carrierreceiving cavity is configured to defined keyways and wherein the perimeter of said first portion of said second body is configured to define keys for mating with said keyways to ensure that said carrier means is properly oriented relative to said socket means.

5. Apparatus according to any preceding claim wherein a portion of said first portion intended to first enter said carrier-receiving cavity forms a beam for both facilitating the entry of said first portion into said carrier-receiving cavity and for cooperating with said resilient end portions oi said contact means to retain said carrier means in engagement with said socket means.

6. Apparatus according to any preceding claim wherein said second body is configured such that the conductive legs of a DIP contained within the DIP-receiving cavity do not extend beyond the outer most extremes of said first portion.

7. Apparatus for connecting a dual in-line packaged electrical component to a circuit board, substantially as hereinbefore described with reference to, and as illustrated in, the accompanying drawings.

8. Any novel feature or combination of features herein disclosed.