Terminal positioning method and construction

Abstract

An improved method and construction for positioning a plurality of socket terminals on an electrical circuit board in a predetermined configuration prior to the solder connection thereto. A sheet of electrically insulative, flexible, resinous plastic material is provided with a plurality of holes in an array conforming to the desired positioning of the sockets on the circuit boards. The socket terminals are provided with an enlarged generally cylindrical head including an intermediate groove such that the heads extend into the holes and are adapted for frictional snap engagement with the sheet. The sheet with the array of sockets temporarily held thereby is positioned on the circuit board which is then conventionally soldered so as to electrically and mechanically fix the sockets to the board. Thereafter, the sheet may be removed. The enlarged head of the circuit terminal is provided with leading edge sheet contacting surface to enable the terminals to be push positioned into the holes without injuring the sheet.

Description

BACKGROUND AND OBJECTS OF THE INVENTION

This invention deals with an improved construction and method of positioning a plurality of socket terminals on an electrical circuit board such as a printed circuit board having a plurality of openings into which the pin portions of the socket terminals can be hand assembled upon the circuit board in the desired position, such involves undue time consumption; and, accordingly, it is generally accepted practice to utilize socket terminal carrier assemblies for group insertion into the printed circuit board.

Such carrier assemblies are conventionally in the form of an aluminum plate having a plurlity of downwardly extending thin fingers for entrance into the open sleeve portion of the socket terminals such that the terminals are held thereby and inserted into the PC board as a group in the desired array. Such system has found wide acceptance for socket terminals destined for single in-line and dual in-line positioning on circuit boards but are not particularly adapted with the recently introduced more complex pin grid arrays associated with electronic circuitry, i.e., integrated circuits. Thus it would be unwieldy to produce a conventional aluminum carrier having downwardly extending fingers in the desired number and geometric configuration necessary to group insert the number of socket terminals associated with such integrated circuit pin grid arrays. Accordingly, it would be desirable to be able to simply and effectively group position socket terminals in both simple and complex pin arrays by the same means.

Another problem associated with the use of presently utilized conventional socket terminal carrier assemblies such as the above-described aluminum plates is that there is both considerable tooling cost and lead time required to produce such carriers. Accordingly, a further desirable feature would be the provision of a means by which both lead time and tooling cost could be substantially reduced.

Still another problem associated with the use of aluminum carriers as above-described is that the slender fingers which are inserted into the lead socket can sometimes undesirably alter the electrical conductive properties of the sleeve portion of such sockets as by scratching or otherwise damaging the internal surface thereof. Such sleeves are very often provided with a very thin gold plate for contact of the pins of the active electrical or electronic circuit element and, accordingly, can be fragile and unnecessary contact therewith should be avoided. Also as when such aluminum carriers are carelessly removed, it is possible to actually pull out the contact sleeve of one or more sockets thus rendering the device useless. Accordingly, a further object of the present invention is the provision of a system and means whereby internal portions of the lead sockets are not contacted during the group insertion thereof into the printed circuit board.

It is also important that inspection of the soldered connections, particularly the connections between the upper portion of the printed board and the downwardly extending lead socket pin, not be obscured or otherwise hindered from proper inspection prior to the removal of the carrier element. Accordingly, a further object of the present invention is the provision of an improved system and means for group insertion of lead sockets which do not hinder solder inspection.

The above objectives as well as other objectives as will hereinafter be more apparent are achieved in the present invention by the provision of a construction for temporarily positioning a plurality of , and in those cases where the top of the sheet is supported and the pins inserted from below, then the sheet will contact the upper surface 66.

An inwardly extending groove 68 is positioned intermediate the enlarged head 50 and is generally of V-shaped configuration brought about by the convergence of an upper inwardly, downwardly extending wall 70 and a lower, inwardly, upwardly extending wall 72. The diameter of the openings 32 terminate in a circumferential edge surface 74. As shown in FIG. 7, the movement of the lower head section 76 towards and into the opening 32 will cause a slight downward extension or bending of the edge 74, i.e., a sort of slight wiping action such that the peripheral portions of the sheet 30 surrounding the hole 32 will be downwardly directed into contact with the lower wall 72 within the groove 68. Conversely, if the socket 34 is inserted in the opposite direction, the slight deformation of the sheet surrounding the openings 32 will be in the opposite direction and the terminal edge 74 thereof will abut the upper slanted wall surface 70. The thickness of sheet 30 is less than the height of groove 68.

Alternatively and as shown in FIG. 7A, the dimensions of the groove 68 and the openings 32 may be such that a lesser deflection is caused such that the terminal edge 74 merely extends into the groove 68. The important aspect is that the relative dimensions are such that the socket head 50 is securely grasped by the sheet 30 in the various holes 32 thereof such that they cannot easily dislodge therefrom during normal handling of the carrier and socket subassembly prior to insertion on the PC board. It is also possible to utilize groove and hole configurations which are non-circular so long as they are appropriately matched to facilitate the necessary firm connection between the two. It is, accordingly, anticipated that some useful functions such as rotational orientation of a socket in a particular manner with respect to the carrier sheet 30 and, accordingly, ultimately with respect to the circuit board can be achieved by the use of triangular, square, oblong, rectangular, etc. openings.

Turning now to FIGS. 8 and 9 of the invention, a modified form of the carrier 30a is shown wherein the sides thereof include downwardly extending flanges 82 of a length such that the terminal surface or edges 84 thereof contact the upper surface of the PC board in such a manner as to hold the pin portions of the sockets slightly above the upper surface of the PC board so as to promote desirable solder filleting therebetween.

While there is shown and described herein certain specific structure embodying this invention, it will be manifest to those skilled in the art that various modifications and rearrangements of the parts may be made without departing from the spirit and scope of the underlying inventive concept and that the same is not limited to the particular forms herein shown and described except insofar as indicated by the scope of the appended claims.

Claims

1. A construction for temporarily positioning a plurality of socket terminals on an electrical circuit board in a predetermined configuration prior to solder connection thereto, comprising a sheet of relatively thin, flexible, electrically insulative, resinous plastic material having a plurality of holes extending therethrough, said holes arranged in a planar configuration about said sheet to correspond with said predetermined positioning of said socket terminals in said circuit board, a plurality of socket terminals each having a pin adapted for insertion into an opening in said board at their lower end and an enlarged generally cylindrical head at their upper end, said enlarged head having upper and lower head sections defined by an inwardly extending perimetal perimetrical groove intermediate the height thereof and of a lateral extent less than that of said upper and lower sections, said holes of a perimetal perimetrical extent less than that of said head sections but generally corresponding to or slightly greater than that of said groove, said terminals adapted for positioning upon said sheet with the heads thereof extending through said holes and the sheet extending into said grooves and wherein the leading edge of at least one of said upper and lower head sections is provided with a longitudinally oriented, sheet contacting surface to enable said terminals to be push positioned into said grooves.

2. The invention of claim 1 wherein the geometric configuration of said holes corresponds with that of said grooves.

3. The invention of claim 2, said holes being circular.

4. The invention of claim 1, said head section sheet contacting surface being a curcumferential chamfer chamfered surface.

5. The invention of claim 4, said chamfered surface provided on the lower portion of said lower head section.

6. The invention of claim 4, said chamfered surface provided on the upper portion of said upper head section.

7. The invention of claim 4, said chamfered surface provided on both the lower portion of said lower head section and the upper portion of said upper head section.

8. The invention of claim 1, said head section sheet contacting surface being provided on the leading edges of both said upper and lower head sections.

9. The invention of claim 1, said groove being of substantially V-shaped configuration.

10. The invention of claim 1, said sheet including downwardly extending edge flanges having terminal edge surfaces adapted to contact the upper surface of said circuit board so as to hold portions of said socket terminal pins above said board during soldering of said pins thereto.

11. The invention of claim 1, said sheet being substantially clear Mylar.

12. The method of group positioning a plurality of socket terminals on an electrical circuit board in a predetermined configuration prior to solder connections thereto, comprising forming a plurality of holes in a sheet of relatively thin, flexible, electrically insulative, resinous plastic material in an array at least including said predetermined configuration, each of said socket terminals having a head of enlarged, generally cylindrical configuration and having an inwardly extending perimetal perimetrical groove intermediate the height thereof so as to define upper and lower sections of said head, said holes of a perimetal perimetrical extent less than that of said head sections but generally corresponding to or slightly smaller than that of said intermediate groove, the leading edge of at least one of said head sections provided with a longitudinally oriented sheet contacting surface, supporting one surface of said sheet and thereafter inserting the the heads of a plurality of socket terminals from the opposite surface of said sheet into said holes in said predetermined configuration such that said longitudinally oriented surface initially contacts peripheral edge portions of said sheet defining said holes so as to slightly deform said edge portions in the direction of head insertion until said sheet edge portions snap into said groove.

13. The method of claim 12 wherein said socket terminals are inserted into said holes head first.

14. The method of claim 12 wherein said sockets terminals are inserted into said holes head last. 15. The invention of claim 1 wherein the thickness of said sheet is less than the height of said groove. 16. The invention of claim 1 wherein said sheet is Kapton. 17. The method of claim 12 and further including the steps of,

thereafter positioning said terminals while held by said sheet on said circuit board,

and thereafter group soldering said terminals to said board while said sheet holds said terminals. 18. The method of claim 17 and further including the step of removing said sheet from said terminals after the terminals are soldered to said board by progressively pealing said sheet beginning at one end thereof, from said terminals. 19. A construction for temporarily positioning a plurality of terminals on an electrical circuit board in a predetermined configuration prior to solder connection thereto, comprising a sheet of relatively thin flexible material having a plurality of holes extending therethrough, said holes arranged in a planar configuration about said sheet to correspond with said predetermined positioning of said terminals in said circuit board, a plurality of terminals each having a pin adapted for insertion in said board at their lower end and an enlarged head at their upper end, said enlarged head having upper and lower head sections defined by an inwardly extending perimetrical groove intermediate the height thereof and of a lateral extent less than that of said upper and lower sections, said holes of a perimetrical extent less than that of said head sections but generally corresponding to or slightly greater than that of said groove, said terminals adapted for positioning upon said sheet with the heads thereof extending through said holes and the sheet extending into said grooves. 20. The method of group positioning a plurality of terminals on an electrical circuit board in a predetermined configuration prior to solder connections thereto, comprising forming a plurality of holes in a sheet of relatively thin flexible material in an array at least including said predetermined configuration, each of said terminals having a head of enlarged configuration and having an inwardly extending perimetrical groove intermediate the height thereof so as to define upper and lower sections of said head, said holes of a perimetrical extent less than that of said head sections but generally corresponding to or slightly smaller than that of said intermediate groove, supporting one surface of said sheet and thereafter inserting the heads of a plurality of terminals from the opposite surface of said sheet into said holes in said predetermined configuration to establish contact with peripheral edge portions of said sheet defining said holes so as to slightly deform said edge portions in the direction of head insertion until said sheet edge portions snap into said groove.