US3760340A

US3760340A - Circuit board socket

Info

Publication number: US3760340A
Application number: US00193913A
Authority: US
Inventors: L Friend
Original assignee: EI Du Pont de Nemours and Co
Current assignee: EIDP Inc
Priority date: 1971-10-29
Filing date: 1971-10-29
Publication date: 1973-09-18
Anticipated expiration: 1990-09-18

Abstract

An electrical disconnect socket comprising a forked body having a spring clip wrapped around the fork prongs. The clip includes a pair of spring arms extending into the space between the prongs for forming an electrical connection with a lead inserted into the socket.

Description

0 llniied States Param [191 I1 1I 3,766,386

lFriend [451 Sept. i8, i973 [54] CIRCUIT BOARD SOCKET 1,678,082 7/1928 Rottenburg .Y 339/262 R 3,120,415 2/1964 Durocher 339/256 R [75] Inventor: Lndsay C- Frmd Camp H1", Pa- 3,348,189 Io/I967 colare et aI. 339/32 R [731 Assign@ I- d P3J 1e N;fI *ld FOREIGN PATENTS 0R APPLICATIONS ompany mmg on e' 651,746 10/1937 Germany 339/262 R [22] Filed: Oct. 29, 1971 '[2] l APPL Nm 193 913 Primary Examiner-Joseph H. McGlynn Attorney-Thomas Hooker [521 U.s. CI 339/262 R [511 Im. cI non 13/06 [57] ABSTRACT v [58] Field of Search 339/255, 256, 258, A decimal dlsconnw Socket COmPrISmg a forked 339/259, 262 body having a spring clip wrapped around the fork prongs. The clip includes a pair of spring arms extend- [56] References Cited ing into the space between the prongs for forming an UNITED STATES PATENTS electrical connection with a lead inserted into the k t. 3,504,331 3/1970 Andersom... 339/256 R Soc e 1,589,066 6/1926 Gibbons 339/259 F 18 Claims, 14 Drawing Figures PATENIEUSEPI Bls SHEU 1 UF 3 INVENTOR. LINDSAY C. FRIEND THOMAS HOOKER, HI'S A'HIOYYIQL,

PATENTED SEP 8 ISYS SHEET 2 UF 3 INVENTOR.

lLmDsAY c. FmEND THOMAS HOOKER,

His vso'rnel INVENTOR. LIND SAY C. FRIEND THOMAS HOOKE R,

His AHoYneL) PATENTEU SEH 81975 snm 3 of 3 loo loa

CIRCUIT BOARD SOCKET The invention relates to a disconnect socket preferably mounted on a circuit board for removably receiving leads, such as those extending from integrated circuit or other type modules to be mounted on the board.

The socket is formed from a forked body having a spring clip wrapped around the prongs of the fork with spring arms extending from the clip and into the space between the prongs. In one embodiment the spring clip is formed from a pair of like clips members each of which includes albody secured to one side of the fork and having a holding tab which extends around one prong into overlying relationship with the body of the other clip member on the other side of the fork. In other embodiments the spring clip is formed from an integral clip member which is wrapped around the prongs. In each embodiment the fork is provided with a fusable coating so that when the clip is positioned on the prongs and the assembly is heated a physical and electrical connection is formed between the clip and the fork. In the disclosed embodiments a circuit board or a wire wrap tail extends from the fork Afor forming an electrical connection between theclip and a circuit element.

In two of the embodiments the spring fingers carried by the spring clips are joined to the clip at one end with the medial portions of the fingers bowed into the lead receiving space and the free ends confined behind stops which prevent flexing of the ends outwardly of the socket. Upon insertion of a lead into the socket the stops prevent the free ends of the spring fingers from being flexed outwardly of the socket thereby increasing the contact pressure and. forcing elongation of the spring fingers. In the embodiment in which the spring clip is formed from two preforms, the ends of the holding tabs extend behind the fingers thereby preventing flexing of the fingers outwardly of the socket. Y

l In a further embodimentof the invention extended length cantilever" spring fingers are provided for increased contact pressure. l Other objects and features of the invention will become apparent as the description proceeds, especially when taken in conjunction with the accompanying drawings illustrating the invention, of which there are three sheets.

THE DRAWINGS FIG. l is a view of a clip preformused in forming a socket according to the invention; y

FIG. 2 is a perspective view of a bifurcated socket member;

FIG. 3 is a perspective view of a disconnect socket with a spring clip formed from a pair of preforms as illustrated in FIG. l and a member as illustrated in FIG. 2;

FIG. 4 is a top view of the socket of FIG. 3; FIGS. 5, 6 and 7 are sectional views taken respectively along lines -5, 6-6 and 7-7 of FIG. 3;

FIG. 8 is a view of a preform used in a different embodiment of the invention;

FIG. 9 is a perspectiveview of the disconnect socket formed with a preform of FIG. 8;

FIG. l0 is a sectional view taken along line 10-10 of FIG. 9;

FIG. 1l isa view of a clip preform used in a further embodiment of the invention;

FIG. I2 is a side view of a disconnect socket having a spring clip formed from a preform as illustrated in FIG. 1l;

FIG'. 13 isa sectional view taken along line 13.-13 of FIG. l2; and

FIG. 14 is a top view of the socket of FIG. 12.

Disconnect socket l0 illustrated in FIG. 3 is formed from a bifurcated forked socket body l2 illustrated in FIG. 2 having spring clip 13 comprising a pair of spring clip members 14 wrapped around the prongs of the fork. The fork 12 comprises an elongate member preferably stamp-formed from brass or other suitable metal. A pair of spaced apart prongs 16 extend from one end of the fork and define a lead receiving space 18 therebetween. Bevels 20 are provided at the free end of the prongs and extend into space 18 to facilitate insertion of a lead into the completed socket. The side walls of the prongs are preferably flat.

An elongate tail 22 extends away from fork base 24 and includes a square circuit board mounting portion 26 adjacent the base and a reduced section square tail 28 extending from the mounting kportion 26. Dimples 30 may be formed on the comers of portion 26 to facilitate mounting of' socket l0 in a circuit board hole. Tail 28 may be used for forming an electrical connection with a circuit element by means of a disconnect socket or a wire wrap connectiomMounting portions 26 may be soldered to a circuit board. The socket body 12 is preferably provided with a thin coating of tin or solder.

FIG. l illustrates a blanked spring clip preform 14 preferably formed from strip stock having a high yield strength, such as beryllium copper. The preform 14 includes an elongate generally rectangular body 32 with a tab 34 extending laterally from one side thereof. The width of the tab 34 is tapered at free end 36. A spring finger 38 is cut out of the interior of the body 32. The finger extends along the longitudinal axis of the body and is joined thereto at body end 40. The sides of the finger 38 are spaced from the sides of the body by slits 42. An opening 44 is provided in the body between the free end 46 of the spring finger and body end 48. Body end 40 projects laterallybeyond the edges of the body at 50.

In socket l0 a pair of bent clip members 14 are fitted about opposite prongs 16 as illustrated to form clip 13. In each preform 14 tab 34 is bent through a right angle along lines 52. Ends 40 are bent outwardly along line 54 and the spring finger 38 is bowed toward the opposing tapered tab end 36. End 48 is bent up through 180 along lines 56 o n the side of the body 32 away from the tab so that it rests flush upon the outer surface of the body and forms a stop for the finger.

When the formed clip members are positioned on fork prongs 16, the body portions 32 rest flush upon the sides of prongs 16 with the spring fingers 38 extending into the lead receiving space 18 between the prongs; the t'lat tab portions 58 rest flush upon prong end faces 60 and the tapered tab portions 36 rest upon the body portions of the other clip member. The ends of portions 36 extend partially across the linger cut-out 62 and cooperate with the body ends 48 in preventing flexing of the springs out of the socket.

After the clip 13 has been positioned in place on the prongs I6 the socket is heated sufficiently to melt the solder or tin plating on fork l2 and thereby form a physical and electrical connection between the fork and each of the clip members. Because of the'large area of contact between the fork and each clip member there is a low contact resistance at the connection.

In the assembled socket contact points 64 on spring fingers 38 normally engage each other. Lead 66 is moved into the open socket end 68 and is guided into space 18 by the prong bevel surfaces 20 and the outwardly bent clip ends 40. As the lead moves into the space it engages the fingers 38 and forces the same outwardly of the socket so as to form a high pressure electrical connection between the lead 66 and the contacts 64. The bent back clip ends 48 and tab ends 36 assure that insertion of oversize leads or leads misaligned with the longitudinal axis of the clip do not stress the spring fingers beyond their elastic limits. In this way permanent deformation of the fingers is eliminated. Lead 66 may be removed from the socket and reinserted without appreciable decrease in the contact pressure between the springs and the lead. Prong base 24 forms a stop for preventing over-insertion of the lead 66 into the socket.

In socket 10 the folded back body ends 48 serve as wearing surfaces for the spring ends 46 so that after initial engagement between the spring ends and the body ends the spring ends are prevented from moving outwardly of the socket while the springs themselves are free to elongate. In this manner the lead contact pressure is increased over conventional sockets utilizing cantilever spring arms having unsupported free ends.

While lead 66 illustrated in FIGS. 3 thru 7 is cylindrical in cross section, it is obvious that socket 10 may be used for forming an electrical connection with a tabular lead of generally rectangular cross section or with other types of leads. As illustrated in FIGS. 4 and 5, the contact points 64 extend across practically the entire width of the opening 18 for establishing electrical connections with leads inserted into the space.

In socket 10 the spring clip 13 is formed from a pair of like clip members 14 wrapped around the fork prongs 16. The clips 13 include a pair of bodies 32 secured to opposite sides of the prongs 16, each carrying a spring arm extending into the space 18.

Socket 70 illustrated in FIGS. 9 thru 11, is similar to socket 10 with the exception that the spring clip is formed from an integral preform 72, illustrated in FIG. 8, as opposed to the two member spring clip used in socket l0. Socket preform 72 includes a pair of like spring bodies 74 each having a spring nger 76 formed from the medial portion thereof and joining body end 78. As in spring clip members 14 a clearance 80 is provided between the sides of the fingers and the bodies. Body ends 82 are provided with cut-outs at the ends of the springs.

The bodies 78 are joined by connecting member 86 and a laterally extending tab 88 extends from the side of one body member away from member 86. Tangs 90 extend from tab 88.

Spring clip member 72 is preformed for mounting on prongs 16 of a fork 12 by bending the clip member along lines 92 to form a generally rectangular shaped clip 73 with tangs 90 engaging the outside of the body 78 remote from tab 88. The fingers 76 are bent inwardly of the clip, body member ends 78 are bent outwardly to form lead guides and body member ends 82 are bent up flush against the outside of the bodies to provide stops for the springs. The clip member 72 may be formed around the prongs 16 of a fork 12 or may be preformed and then positioned about the prongs. After the clip is positioned on the prongs the assembly is heated to form the desired electrical and physical connection between the spring clip and the fork body. The spring fingers 76 extend into the interior of the lead receiving space 18 between the prongs to form an electrical connection with a lead 94 moved into the socket. As in socket 10 the spring ends 96 are prevented from movement outwardly of the socket so that movement of a lead into the socket elongates the spring to stress the entire lengths thereof and form high pressure electrical connections.

FIGS. 12 thru 14 disclose a disconnect socket 100 in which a spring clip 102 formed from preform 104 of FIG. l1 is mounted on the ends of the prongs 18 of a fork 12. The preform 104 includes a flat strip 106 having a pair of cantilever spring arms 108 extending from one edge thereof. The width of the arms is tapered away from the strip to assure uniform loading upon reception of a lead. As illustrated in FIG. 11, the longitudinal axis of the spring arms diverge from each other outwardly of the strip. Arm recesses 110 are formed on the opposite edges of the strip from the spring arms 108.

The clip preform 104 is bent to form spring clip 102 having a rectangular body which fits over the free ends of prongs 18. The strip portions 112 adjacent the spring arms 108 are bent outwardly to provide lead-ins cooperable with the bevel surfaces 20 on the prongs 16 for guiding a lead into space 18. Spring arms 108 are bent outwardly of the clip through an angle of approximately so that the arms extend back past strip portions 112 and into lead receiving space 18. Rounded contact points 114 are formed on the ends of the arms. After the clip has been mounted on the prongs the assembly is heated to form an electrical connection between the clip and the body as in

sockets

10 and 70. The cut-outs 110 prevent binding between the spring arms and the strip 106.

Insertion of a lead into the socket 100 forces the arms 108 apart to form the desired electrical connection between lead and contacts 114. The increased length of the arms 108 resulting from the bent-back configuration achieves a higher contact pressure than in conventional sockets in which the arms extend directly into the interior of the socket from a bend or strip type side member. As in the previous two sockets, the prong base 24 limits insertion of the lead into space 18.

The contact points of all three

spring clips

13, 73 and 102 may be coated with a precious metal to reduce contact resistance with the lead.

While I have illustrated and described preferred embodiments of my invention, it is understood that these are capable of modification, and I therefore do not wish to be limited to the precise details set forth, but desire to avail myself of such changes and alterations as fall within the purview of the following claims.

What I claim as my invention is:

1. An electrical disconnect socket comprising a socket body having a pair of prongs spaced apart on opposite sides of a lead receiving recess, and having a spring clip wrapped around the outer periphery of the prongs and including a pair of spring members; each spring member being located to one side of said prongs and including a strip portion extending across the space between the prongs to cooperate with the prongs in defning the periphery of the recess; electrical connections between each strip portion and the prongs; each spring member including a flexible contact finger integral with a strip portion, extending awayy from the ends of said prongs and having a lead contact located within the recess.

2. A socket as in claim l wherein each spring member comprises an elongate flexible finger extending from a strip portion at the edge thereof adjacent the free ends of said prongs, past the surface of the strip member facing away from the recess and into the recess.

3. An electrical disconnect socket comprising a socket body having a pair of flat sided prongs spaced apart on opposite sides of a lead receiving recess and a pair of spring members each comprising a flat strip of metal stock resting flush upon sides of the prongs and in electrical connection therewith, said spring members cooperate with the prongs in defining the periphery of the recess; each spring member including a flexible contact finger formed from the portion of said stock between the prongs and bent into the recess.

4. A socket as in claim 3 wherein each of said pieces of flat metal stock comprise an integral part of a single spring clip wrapped around said prongs.

5. A socket as in claim 3 wherein said spring members include means for limiting movement of the free ends of the fingers outwardly of the recess.

6. An electrical disconnect socket comprising a pair I of prongs spaced apart on opposite sides of a lead receiving recess and a pair of U-shaped spring clips; each spring clip being mounted on one prong with a strip portion extending across the space between the prongs to cooperate with the prongs in defining the periphery of the recess; each strip portion including an integral spring contact located within the recess'.

7. A disconnect socket comprising a base having a prong extending vtherefrom and means for forming an electrical connection with a circuit element; and a springclipwrapped around the prong and including av l0. A disconnect socket as in claim 9 wherein said electrical connection comprises a fused joint between the clip and each prong.

l1. A disconnect socket as in claim 9 wherein one end of each spring finger is joined to the clip and the other end of each finger is free of the clip and the clipl includes stops for preventing movement of said other ends outwardly of the socket.

13. A disconnect socket including a fork having a pair of longitudinally extending prongs and means for serted therein.

13. A disconnect socket as in claim l2 wherein said spring clip includes a pair of like clip members each including an L-shaped tab extending around one of said prongs with the free end thereof resting on the other clip member.

14. A disconnect socket as in claim 13 wherein said `tab free ends extend into the deflection paths of said spring fingers.

l5. A disconnect socket as in claim 13 wherein one end of each spring finger is secured to a spring member andthe other end is free and each spring member includes a stop engagable with the other end of a spring finger to prevent movement of such end outwardly of the socket while permitting elongation of the spring finger. v

16. A disconnect socket including a forked socket body having a pair of spaced prongs; a spring clip mounted on said prongs and in electrical connection therewith including a pair of spring arms extending into the space between said prongs for establishing an electrical connection with a lead inserted therein.

17. A disconnect socket as in claim 16 wherein said spring clip includes a pair of like clip members secured to opposite sides of the prongs and wherein said spring fingers extend from the clip members adjacent the free ends of the prongs into the space between the prongs and include free ends located adjacent the base of the prongs.

l. A disconnect socket as in claim 17 wherein said clip is wrapped around both of said prongs.

. n: t n :i:

Claims

1. An electrical disconnect socket comprising a socket body having a pair of prongs spaced apart on opposite sides of a lead receiving recess, and having a spring clip wrapped around the outer periphery of the prongs and including a pair of spring members; each spring member being located to one side of said prongs and including a strip portion extending across the space between the prongs to cooperate with the prongs in defining the periphery of the recess; electrical connections between each strip portion and the prongs; each spring member including a flexible contact finger integral with a strip portion, extending away from the ends of said prongs and having a lead contact located within the recess.

2. A socket as in claim 1 wherein each spring member comprises an elongate flexible finger extending from a strip portion at the edge thereof adjacent the free ends of said prongs, past the surface of the strip member facing away from the recess and into the recess.

6. An electrical disconnect socket comprising a pair of prongs spaced apart on opposite sides of a lead receiving recess and a pair of U-shaped spring clips; each spring clip being mounted on one prong with a strip portion extending across the space between the prongs to cooperate with the prongs in defining the periphery of the recess; each strip portion including an integral spring contact located within the recess.

7. A disconnect socket comprising a base having a prong extending therefrom and means for forming an electrical connection with a circuit element; and a spring clip wrapped around the prong and including a pair of cantilever spring fingers extending into the lead receiving space adjacent the prong and inside the clip and a band portion completely surrounding the prong and the lead receiving space, and an electrical connection between the clip and prong.

8. A disconnect socket as in claim 7 wherein said base includes a pair of prongs and said clip is wrapped around both of said prongs.

9. A disconnect socket as in claim 8 wherein an electrical connection is formed between said clip and each of said prongs.

10. A disconnect socket as in claim 9 wherein said electrical connection comprises a fused joint between the clip and each prong.

11. A disconnect socket as in claim 9 wherein one end of each spring finger is joined to the clip and the other end of each finger is free of the clip and the clip includes stops for preventing movement of said other ends outwardly of the socket.

12. A disconnect socket including a fork having a pair of longitudinally extending prongs and means for forming an electrical connection with a circuit element; and a spring clip comprising a pair of clip members mounted on opposite sides of said prongs with each clip member in electrical connection with each of the prongs, a spring finger extending from each clip member into the lead receiving space between the prongs for forming an electrical connection with a lead inserted therein.

13. A disconnect socket as in claim 12 wherein said spring clip includes a pair of like clip members each including an L-shaped tab extending around one of said prongs with the free end thereof resting on the other clip member.

14. A disconnect socket as in claim 13 wherein said tab free ends extend into the deflection paths of said spring fingers.

15. A disconnect socket as in claim 13 wherein one end of each spring finger is secured to a spring member and the other end is free and each spring member includes a stop engagable with the other end of a spring finger to prevent movement of such end outwardly of the socket while permitting elongation of the spring finger.

18. A disconnect socket as in claim 17 wherein said clip is wrapped around both of said prongs.