CA1271819A

CA1271819A - Electrically shielding

Info

Publication number: CA1271819A
Application number: CA000536842A
Authority: CA
Inventors: Walter Phelps Kern
Original assignee: Teradyne Inc
Current assignee: Teradyne Inc
Priority date: 1986-08-05
Filing date: 1987-05-11
Publication date: 1990-07-17
Also published as: CA1271819C; GB2193604A; FR2602630B1; JPS6342199A; GB8713172D0; GB2193604B; FR2602630A1; DE3723968A1; DE3723968C2; JPH0239119B2

Abstract

Abstract A shielding device, as for spring pins, is provided by providing a base having shielding holes, grounding holes, and a trough connecting them with an interconnected covering, providing within the shielding holes insulators with element holes therethrough.

Description

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ELECTRICAL~Y SHIELDING
Field of the Invention This invention relates to electrically shielding, and more particularly, in preferred embodlments, to the coaxlal ~hielding of sprlng pins.
Backaround of the Invention The desirablllty of shleldlng elements of electrlcal clrcults, ln approprlate lnstances, ls well known. Coaxially shlelded ~prlng plns for u6e ln connectlon wlth prlnted circuit boards ("PCB~") are known.
Su-marY of the Invention I have discovered that coaxlal 6hieldlng may be provlded, reliably, at low expense and consi6tently wlth hlgh ~hlelded element denslty, by provldlng an lnsulator base having shlelded element and groundlng element mountlng holes, the lnner wall of a grounding element mountlng hole belng ln conductlve electrlcal communlcatlon with a shield around a shlelded element mountlng hole and spaced therefrom by lnsulatlng materlal.
Accordlng to a broad aspect of the lnventlon there ls 0 provlded an electrlcally shleldlng devlce which comprises~
a base, said base belng formed of in~ulating materlal and havlng thereln a shleldJng hole and a shleld connectlng hole, . sald ~hleldlng hole havlng posltioned thereln a metalllc shleld therearound, ~ 1 an insulator wlthin ~aid shield, and an element hole in said insulator, and said shield connecting hole having positioned therein an electrically conductive layer, said layer being in electrical communication with said shield.
According to another broad aspect of the invention there i8 provided the method of fabricating a æhielding device which comprlses forming an lnsulatlng base, provlding thereln a flrst hole and a second hole, coating said base over said holes with a layer of conductlve materlal, placing in said first hole an insulatlng material with a third hole therethrough, and electrlcally interconnecting the coatlngs in said first and second holes.
In preferred embodlments, the insulator base is a unltary ~tructure molded from polyphenylene sulfide reinforced with glass and containing a multlpllcity of spring pin mountlng holes orlented ln pairs, one sprlng pln mountlng hole of each palr belng spaced by a polytetrafluoroethylene lnsulatlng annulus from an electroless nlckel ghleld around the annulus, the other sprlng pin mountlng hole of each palr belng conductlvely connected to the ~hleld by a contlnuum of the electroless nlckel.
In another aspect of the inventlon, I have dlscovered that such a coaxlal shleldlng devlce may be provlded by formlng an ln~ulatlng base containlng a palr of holes therethrough, platlng the base wlth metal, removlng the metal from top and bottom surfaces of the base, and formlng ln one of the holes an annulus of lnsulatlng materlal. In a preferred embodlment a bllnd slot ls ~d ~.27181~

provided between the two holes before plating.
Preferred E~bodiment Following is a description of preferred embodiments of the device and method of the invention.
Drawing~
There is shown in:
Flgure 1 an lsometric view of a broken-away portion showing one shleld portion of the preferred embodiment of the device.
Flgure 2 a correspondlng lsometric view illustrating an earlier stage ln the preferred embodlment of the method.
Flgure 3 a dlagrammatlc plan vlew of a broken away portlon of the devlce.
Flgure 4 a plan vlew on a smaller scale of an arrangement of sald devices.
Figure 5 a sectional view taken at 5-5 of Figure 3.
Figure 6 a correspondlng sectlonal vlew showlng a second devlce cooperatlng wlth a flrst in order to ~ecure therebetween a sprlng pln.
8tructure There i~ shown ln Flgure 3 an enlarged plan vlew, and ln Flgure 1 an lsometrlc vlew, of a portlon of one of the devlce~, indlcated generally at 10, of the lnventlon. In use, elght of these devlce~ 10, the lnner and outer walls 12 and 14 of whlch are coaxlally arcuate (O.D. 10 lnches) are abutted to form an arrangement annular ln horlzontal cro~s-sectlon, as shown in plan vlew ln Flgure 4.

~ 3 71~

Referring to Figures 2 and 5, each devlce 10 has a base 16 formed by lnjection molding of glass-filled (40%) polyphenylene sulfide (sold by Phillips Chemlcal Company under the trademark RYTON R-4). ~xtending through base 16 are cylindrically annular layers 18, 20 of dull (for better adhesion) electroless nlckel.
The layer extends ln a continuum along the floor 22 and sides 24, 26 of bllnd slot 27 and therefrom in portlons 28, 30 of counterbore 32 and cylindrlcal portion 34 wlthin hole 36. Annular ca~t tetrafluoroethylene lnsulator 38 ca~tlng materlal ~sold by DuPont under the trademark TEFZEL) iB wlthln electroless nlckel layer 18, 20 and fill~ slot 27. Hole 40 wlth counterbores 42 is provlded ln lnsulator 38.
As ~hown in Flgure 6, two unlt~ 10 are brought together wlth sprlng plns indlcated generally at 43 held therebetween ln one set of counterbores 32, 42 for each sprlng pln. (Counterbores 32, 42 are provided at each end of holes 36, 40 80 that the ring 44 made up of unlts 10 may be used with either surface up, to permlt moldlng a slngle base 16 even though two configurations of base 16 are needed, for example alternatlng around the annulus, one belng a mlrror lmage of the other. The rlng 44 may be held together and down on a PCB (not shown) by screws (not ~hown), and permlts easlly releasably connectlon therethrough wlth another PCB
(not shown).
OPeration Current passlng through sprlng plns 43 ln lnsulator 38 18 electrically shlelded by electrodless nickel completely therearound, the latter belng electrlcally connected wlth the ~ 4 ~ 7181~

ad~acent ground spring pin through a continuing layer of electroless nickel. Hole 36, in which the ground spring pin is located, thus is a shield connecting hole, in that the layer of nickel electrically connects the pin in it to the shield of the adjacent shielded pln.
Hethod The device is made by first molding the base 16, giving it an overall thickness about 0.020 inches greater than ultimately wanted. The entire piece is then given a coating of dull electroless nickel, which extends over top, bottom and throughout the large and snall hole, counterbore, and slot as ~hown ln the uncoated piece ~hown ln Figure 2. About 0.010 inch thlckness ls then removed ~rom top and bottom, removlng wlth lt the nlckel coating thereover. Bushing 38 is then cast.
Other E-bodi~ents Other embodlments wlll occur to those skllled ln the art.

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Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. An electrically shielding device which comprises:
a base, said base being formed of insulating material and having therein a shielding hole and a shield connecting hole, said shielding hole having positioned therein a metallic shield therearound, an insulator within said shield, and an element hole in said insulator, and said shield connecting hole having positioned therein an electrically conductive layer, said layer being in electrical communication with said shield.

2. The device of claim 1 in which said shield and said layer are coatings.

3. The device of claim 2 in which one continuous coating provides said coatings and said electrical communication.

4. The device of claim 3 in which said continuous coating is of plated metal.

5. The device of claim 4 in which said metal is electroless nickel.

6. The device of claim 2 in which said base and said insulator are of plastic.

7. The device of claim 6 in which said insulator is glass-loaded polyphenylene sulfide and said insulator is of castable polytetrafluoroethylene, and said metal is electroless nickel.

8. The device of claim 3 in which a trough connecting said shielding hole and said shield connection hole is covered by said continuous coating.

9. The method of fabricating a shielding device which comprises forming an insulating base, providing therein a first hole and a second hole, coating said base over said holes with a layer of conductive material, placing in said first hole an insulating material with a third hole therethrough, and electrically interconnecting the coatings in said first and second holes.

10. The method of claim 9 in which said base is coated overall, and top and bottom surfaces are thereafter cut to electrically segregate said first and second holes.

11. The method of claim 10 in which a channel connecting said first hole and said second hole is coated therewith to provide said electrically interconnecting.