Pin and socket contact electrical interconnect system

[is] 3,663,931

[45] May 16,1972

United States Patent

Brown

[54] PIN AND SOCKET CONTACT ELECTRICAL INTERCONNECT SYSTEM

[ 72 ] Inventor: Elvin E. Brown, Cedar Rapids, Iowa [ 73 ] Assignee: Collins Radio Company, Dallas, Tex. [22] Filed: Nov. 25,1970

[21] Appl.No.: 92,772

3,363,224 1/1968

3,120,418 2/1964

3,286,222 11/1966

3,270,251 8/1966

Gluntz........

Deakin.......

Drink water, Evans.........

....339/258 339/258 X ....339/258 ....317/101

FOREIGN PATENTS OR APPLICATIONS

1,100,657 1/1968

1,250,743 12/1960

1,526,911 4/1968

Great Britain.....................339/258 R ^Frar>ce...............................339/258 A

France................................339/17 M <7 τΤΛ*........................................339/218 R, 339/256 R SR rid^Cr<i7.....7...............................................H01T9/08

[58] Field of Search..................339/218,258,256,176 177

339/17, 18, 217, 252, 65; 317/101 R, 101 C, 101’

CC, 101 D, 101 CW

[56] References Cited

UNITED STATES PATENTS

3,566,342 2/1971

3,362,008 1/1968

2,977,562 3/1961

Schmitt etal.......................339/217 S ^Berg......................................339/258 ^Benson................................339/17 M

Primary Examiner—Richard E. Moore

Assistant Examiner—Robert A. Hafer

Attorney—Warren H. Kintzinger and Robert J. Crawford t⁵⁷] ABSTRACT

A combined unitary pin and socket contact, receivable in a housing, designed for providing electrical interconnect between parallel stacked circuit boards, with guided entry of pins into contact sockets, and opposite side spring socket contact arms resiliently engaging opposite sides of an inserted pin throughout the entire range of pin lateral float.

Claims, 8 Drawing Figures

<img file="US3663931A_D0001.tif" />

Patented May 16, 1972

3,663,931

Sheet-Sheet 1

<img file="US3663931A_D0002.tif" />

<img file="US3663931A_D0003.tif" />

INVENTOR

ELVIN E. BROWN

<img file="US3663931A_D0004.tif" />

Patented May 16, 1972

3,663,931

Sheet-Sheet 2

<img file="US3663931A_D0005.tif" />

FIG. 3

<img file="US3663931A_D0006.tif" />

<img file="US3663931A_D0007.tif" />

INVENTOR

ELVIN E. BROWN

<img file="US3663931A_D0008.tif" />

Patented May 16, 1972

3,663,931

Sheet-Sheet 3

<img file="US3663931A_D0009.tif" />

<img file="US3663931A_D0010.tif" />

<img file="US3663931A_D0011.tif" />

FIG.8

<img file="US3663931A_D0012.tif" />

INVENTOR

ELVIN E. BROWN

<img file="US3663931A_D0013.tif" />

3,663,931 connector pin projecting through a plated through hole in the circuit board;

PIN AND SOCKET CONTACT ELECTRICAL INTERCONNECT SYSTEM

FIG. 3, a length of dual thickness beryllium copper strip stock used for forming a joined ribbon of the unitary pin and 5 socket contacts;

FIG. 4, a two contact section of joined contact ribbon formed from the dual thickness strip stock of FIG. 3;

FIG. 5, a side elevation view of a unitary pin and socket contact in a ribbon joined state such as indicated in FIG. 4;

FIG. 6, a partially cutaway and sectioned view of two of the unitary pin and socket connectors in place in housing cavities with the pins projecting through a circuit board and the connector units shown in 90° rotated orientation from the connector position of FIG. 2;

FIG. 7, the parallel stacked relation of two circuit boards mounted in interconnected relationship from a side board with a side board pin inserted box socket engaging connection to the first adjacent circuit board and the unitary pin of the 20 connector of the first adjacent circuit board projecting through that circuit board and into box socket engaging contact with a like box socket of the next parallel positioned circuit board; and

FIG. 8, a plurality of circuit boards in interconnected rela25 tion showing a double length pin of one unitary pin and box socket connector extended through a conventional through socket contact of an intermediate circuit board to inserted electrical contact with a box socket of a further spaced parallel circuit board.

Referring to the drawings:

The combined unitary pin and box socket contact 10 of FIG. 1 is formed from a unitary piece of metal with a box socket 11 and a connector pin 12 as an extension therefrom generally in longitudinal alignment with the center axis of the 35 box socket 11. These unitary pin and socket contacts 10 are intended for use with circuit boards or cards 13, such as illustrated in FIG. 2, with the box socket 11 inserted within a connector cavity 14 of a dielectric material housing 15 with the box socket 11 of the connector 10 seated on spaced parallel 40 cavity ledges 16 in the fully inserted box socket seated position. This is with the connector pin 12 extended from housing 15 through a plated through hole 17 of the circuit board 13 where it is structurally and electrically conductively fixed in place by solder 17'. Please note that the plated through hole 17 is provided with an upper pad 18 and a lower flange 19 either of which may be connected to circuitry of the copper clad photo-etched type or any other conductive elements of circuitry that may be connected thereto, and with the pad 18 5Q providing a small degree of spacing for the dielectric material housing 15 from the circuit board 13 the housing 15 is mounted on. Housing 15 may include a plurality of relatively closely spaced, parallel connector cavities in single row, two row or plurality row relation, and is mounted on circuit board _g5 13 as by rivets (detail not shown).

Unitary pin and socket contacts 10 as an item of manufacture are formed from a length of dual thickness beryllium copper strip stock 20, such as shown in FIG. 3, with a 0.025inch thick strip portion 21 for the forming of the pins 12 and a ₆₀ 0.008-inch thick strip portion 22 for the forming of the box sockets 11 with a 45° transition bevel 23 that forms the pin beveled ends 23' at the box socket connected end of the pins 12. While beryllium copper has been the strip material employed for forming the contacts 10, other suitable strip materi65 al could also be used with the strip material being die formed initially to dual opposite end ribbon 24 and 25 interconnected unitary pin and socket contacts 10 as shown in FIGS. 4 and 5. The unitary pin and box socket contacts 10 are initially stamped and die formed by progressive die and stamping steps 70 to have a box socket base side strip 26 from which opposite side inwardly directed spring arm 27 mounting base opposite side strap sections 28 extend, and from which opposite side box socket entrance end strap sections 29 extend, and with the entrance end strap sections 29 mounting inserted connector '5 pin lateral float limiting opposite side inwardly sloped tabs 30.

This invention relates in general to pin and socket contacts, and in particular, to a combined unitary pin and socket contact mounted in a housing associated with a circuit board with the pin projecting therefrom for insertion in the socket portion of another contact mounted in a housing of another circuit board.

It has become advantageous, in many instances, to be able to stack circuit boards in spaced parallel relation with allowance for circuitry including discrete components mounted on boards and to have good reliable electrical interconnect between boards as desired. This entails a desired uniformity of connector resistivity factors and for these to be at relatively low resistivity value through each mated connector. Pin to connector housing insertion hang-up problems must be minimized if not eliminated and current leakage between closely spaced pin connectors must be minimized. Further, compatibility interconnect with existing feed through box contacts is desirable. High stack by increments is a requirement with some units to allow for different component heights on circuit boards. Ease of single contact unit replacement is also highly desired.

It is therefore, a principal object of this invention to provide a combined unitary pin and socket contact, mounted in a housing of a circuit board and having circuit interconnect with circuitry carried by the board, adapted for pin to socket inserted electrical contact with another such contact mounted in a like manner on another circuit board stacked in parallel spaced relation to the first mentioned circuit board.

Another object is to provide mounting of the box socket within a housing mounted on a circuit board with the pin unitary with the box socket extended from the housing and through the circuit board mounting the housing.

A further object is to provide guided relatively free connector pin insertion to box sockets without hang-up.

Another object is to limit connector inserted pin lateral float within a box socket.

Still a further object is to insure substantially uniform balanced opposite side spring socket contact arm resilient engagement with an inserted pin throughout the entire range of pin lateral float.

Features of the invention useful in accomplishing the above objects include, in a pin and socket electrical interconnect system, a combined unitary pin and box socket contact with the box socket in a housing within a housing cavity and the pin extended from the housing and through a circuit board mounting the housing. This is with box sockets recessed within housing cavities to have recessed closed pin entry ends along with housing socket cavity beveled entries and connector pin pencil point chamfered ends, in combination, preventing hang up of connector pins during connector pin insertion. Opposite side coined relatively stiff tabs are provided adjacent the entry end of the box sockets that guide pins being inserted to proper entrance between opposite side resilient spring pin engaging contact arms. Further, the opposite side coined tabs are relatively short inwardly sloped stiff tabs subject to minimal deflection by connector pins being inserted into the box socket and provide mechanical over-stress protection for the resilient spring pin engaging contact arms. The opposite side tabs inner ends overlap the contact pin entrance ends of the spring contact arms that may be tapered in both width and thickness for optimized shortness of spring length with uniform stress therealong.

A specific embodiment representing what is presently regarded as the best mode of carrying out the invention is illustrated in the accompanying drawings.

In the drawings:

FIG. 1 represents a perspective view of applicant’s unitary pin and socket contact;

FIG. 2, a side elevation cutaway and sectioned view with the contact box socket installed in place in the cavity of a dielectric material housing mounted on a circuit board and with the

3,663,931

The box socket base end strap sections 28 and entrance end strap sections 29 are die formed to extend up at substantially 90° from the base side strip 26 and are then, from opposite side tops, bent inwardly at substantially 90° and terminated in spaced parallel longitudinally extended strips 31 and 32 interconnecting respective box socket end straps 28 and 29 and extending generally the length of the box socket 11 from the base thereof to the entrance end where they are terminated in outwardly formed tab ends 33 and 34.

Thus, the box socket 11 is formed, however, with metal removed during the stamping and forming operations so that there is relief space at the corners of the box socket 11 with only strap sections 28 and 29 extending through the 90° corners of the box socket. Further, other than in the area of base side strip 26 where an extension transition interconnect 35 thereof forms the connective transition therefrom to the pin 12 of the unitary pin and box socket connector, portions of the outer end edges of base end strap sections 28, forming the bottom of the box socket 11, seat on spaced parallel ledges 16 within the cavity 14 of housing 15. The transition interconnect 35 between the base side strip 26 of the box socket 11 and the connector pin 12 extends through extension opening 36 from the level of the ledges 16 in cavity 14 within housing 15 and supports the pin 12 generally in longitudinal alignment with the box socket 11 it is an extension of. In addition to the outwardly formed tab ends 33 and 34 at the entrance end of box socket 11, the box socket is also formed with opposite side outwardly formed tab ends 37, 38, and 39 with outwardly formed tabs 37 and 38 extended from opposite side entrance end strap sections 29, that mount connector pin lateral float limiting opposite side inwardly sloped tabs 30, and with outwardly formed tab 39 an entrance end extension of box socket base side strip 26. With a box socket 11 fully inserted within a cavity 14, all the outwardly formed tab ends 33, 34, 37, 38, and 39 are sufficiently down within the rectangular walled portion of cavity 14 that pencil point chamfered pin end 40 of a connector pin 12 being inserted therein does not encounter any insertion bind or hang-up. Further, the cavities 14 are provided with beveled entrance sections 41 to further enhance mating insertion of connector pins 12 to box sockets 11. On pin 12 insertion, the chamfered pin end 40 may come into guided sliding contact with an inwardly sloped surface of a tab 30 to be further guided to proper entrance to the pin electrical contact throat between contact opposite side spring arms 27 just after the outwardly flaired sloped entrance ends thereof.

Please note that the opposite side inwardly sloped spring arms 27 are tapered both in width and in thickness from their base connections with base end strap sections 28 slope inwardly from their base end mountings to a throat constriction terminating in an outward turned sloped flare, and are coin formed for uniform stress in resiliently gripping an inserted pin 12 therebetween with substantially uniform resiliently maintained contact engaging force throughout the range of lateral pin 12 float movement permitted between the inner ends of tabs 30 that are also coin formed tabs to provide the desired closed entry for the connector pins 12 as relatively stiff substantially nondeflectible tabs that thereby prevent mechanical overstress of the spring arms 27. Furthermore, coining of the springs 27 along with the coin forming or swaging of tabs 30 provide a small degree of protective overlap of the spring arm 27 outwardly flared pin entrance ends and the inner tips of tabs 30 to thereby ensure that there be no occurrences of connector pin 12 insertion hang-up on the insertion end of pin contact arms 27. Please note further, that these beryllium copper unitary pin and box socket connectors 10 after being die formed may be heat treated for structural strength and spring arm resilient spring force and then plated with corrosion resistant materials such as silver and/or gold, and that the space between the spaced parallel longitudinally extended strips 31 and 32 and end overlap relatively narrow clearance space provided between the entrance end extremities of spring arms 27 and the adjacent inner ends of overstress tabs 30 insures that all surfaces within the combined unitary pin and box socket connector end be properly plated with corrosion resistant material being plated thereon. The process of applying a corrosion resistant material is presently undertaken while the unitary pin and box socket contacts are still connected to the ribbons 24 and 25 in which form they are fed into and passed through corrosive resistant material plating baths with the ultimately severed and pencil point chamfered pin end 40 not being a critical metal area with respect to requiring a corrosive resistant material coating. This is also applicable with respect to the tab 39 cutoff area from the connective material extension 42 to the ribbon 25 that is provided with sprocket pin receiving openings 43 for the process feeding of the ribbon with the unitary pin and box socket connectors during plating processing thereof and/or for installation feeding thereof during a cutoff and insertion process handling thereof for the unitary pins and box socket connectors 10.

Two of the unitary pin and box socket connectors 10 are shown in FIG. 6 mounted in side by side relationship in two row connector housing 15 with the two connector pins 12 thereof cut off to a one connector engaging pin chamfered end 40 length. FIG. 7, on the other hand, illustrates how these unitary pin end box socket connectors 10 are utilized in contact engaged relationship with a pin 12' mounted in a platedthrough opening 44 of a side board 45 is inserted into electrically conductive connection relation with the box socket 11 that is contained within cavity 14 of housing 15 mounted on circuit board 13 with the pin 12 extension thereof in turn also connectively inserted into a box socket 11 contained in cavity 14 of housing 15' mounted on a circuit board 13' with respective to which the pin 12 extensions may be inserted into plated-through holes 17 and cut off instead of in turn being inserted in another box socket 11. In the circuit board stackup illustrated in FIG. 8, an interconnect relation is shown using a unitary pin and box socket connector 10' with a double length pin 12' that is connected through an intermediate conventional through socket contact 46 of an intermediate circuit board to inserted electrical contact with the box socket 11 of a further spaced parallel circuit board. Please note that the box socket 11 configuration presented as well as combination unitary connector pin and box socket connectors may be mounted in parallel to a circuit board installation in attaining additional connector system flexibility (detail not shown). Further, a box socket that has been produced in accord herewith approximately 0.165 inches long for receiving 0.025inch square connector pins provides highly reliable excellent operational service. This is with such pin and socket connections presenting a resistivity factor generally in the range of three to ten milliohms averaging approximately 5 milliohms and with the connectors rated at 3 amperes.

Whereas this invention is herein illustrated and described with respect to several embodiments hereof, it should be realized that the various changes may be made without departing from essential contributions to the art made by the teachings hereof.