US 3601786 A
Abstract available in
Claims available in
Description (OCR text may contain errors)
United States Patentf Assignee Int.
Weldon L. Brublker Mechanicsburg, Pa. 851,030
Aug. 18, 1969 Aug. 24, 1971 Berg Electronics, Inc. Nee Cumberhnd, Pa.
Inventor Appl. No. Filed Patented WIRE GRIP TERMINAL 3 Claims, 8 Drawing Figs.
US. ("I 339/258 R, 339/95 R, 339/275 R H0]: 13/12 50 Field ofSearch  Referencr: Citeql UNITED STATES PATENTS 3,000,402 10/1962 Olsson m1. 339/242 3,510,831 5/1910 De vim 339/258 Primary Exeiminer-Joseph H. McGlynn AuorneyThoma Hooker ABSTRACT: A wire grip circuit board eyelet with wire-engaging burrs on the edges of the wire grip fingers and the method of making the same.
WIRE GRIP'TERMINAL 1 This invention relates to wire grip terminals and in particular to wire grip circuit board eyelets and the method of making the same. Wire grip fingersin the terminals are provided with wire-engaging burrs on the edges thereof so that when a lead wire is inserted into a terminal, the burrs bite into the wire and hold it relative to the terminal. The burrs are formed by punching the wire grip fingers out of one side of metal'stock and then bending the fingers back through the thickness of the stock into the interior of the terminal.
Circuit board eyelets of the type disclosed in U.S. Pat. Nos. 3,368,188 and 3,504,328, both assigned to Berg Electronics, Inc., utilize wire grip fingers to hold' a lead wire fixed relative to the eyelet prior to and during soldering. Other terminals, such as those disclosed in U. S.'Pat. "No. 3,283,288 also use wire grip fingers for holding a lead prior to and during soldermg. I
In some terminals using wire grip fingers it has been found FIG;laboringpunchingofthefingers from the strip, sharp Burrs adjacent edges 18 are also formed on st'rip1l2 The burrs 22' extend along the sheared edges of each finger'and burrs '22 are formedon the fingers atedges 18' facing strip "12 I around the finger from one end of the strip connecting portion" desirable to increase the gripping ability of the fingers so that leads inserted into the terminals are more 'tig'htly'held against shifting within the terminal; This is particularly true in the case of circuit board eyelets of the type referred to where the eyelets are very small in size and are used to holdleads supporting relatively heavy circuit components. The weight of the components tends to shifi the leads in the eyelet, with the result that the leads may project beneath the bottom of thecircuit board, thereby requiring clipping following soldering. Ad ditionally, the leads may even be pulled out of the eyelets so as to require reinsertion prior'to soldering. The invention improves the wire gripping capacity of circuit board eyelets and other terminals using wire grip fingers by providing sharp leadengaging burrs on the edges of the fingers facing the interior of the terminal. When a lead is inserted into the terminal the fingers are forced apart and the burrs bite into the lead to provide an improved grip on the'lead. I a i The wire gripburrs are formed by a manufacturing process in which the wire grip fingers are punched from the stock forming the eyelet so that burrs are fonned on the edges of the fingers adjacent the stock. The fingers are then pushed back into the finger cutouts in the stock and the stock is rolled to form the body of the eyelet with the burrs on the fingers facing the interior of the eyelet. After rolling of the eyelet, the fingers are bent into the eyelet with the ends of the fingers positioned together within the eyelet. The burrs face the interiorof the eyelet so that they engage leads inserted into the eyelet with improved wire gripping ability.
Other objects and features of the invention will become ap- 20 to the other end of the-portion. The edgesZS of the fingers I facing away from-strip 12 are punching operation.
rounded somewhat during the I ollowing indexing ofstrip ll-i' to the second station of the progressive die, the '16 are moved back into the thickness of strip 12 as illustrated in'FIG'. 3. It is necessary .to position the fingers within' the strip so that the eyelet may be rolled without collapsing the body portion. Movement of the fingers back into the strip does not materially dull the burrs 22". At thesecond station strip 12 is partially blanked to define the P rtion from whic l 11 W 1 will hemmed At the third statimiQblanking ofthe strip-is completed is form eyelet preform 26L Slits 28 are formedirr the top of the preform and the top of the preform is slightly flared. Notches 30. areiform'ed on the bottom of the preform. I v
A At thefourth station, preform 26 is offset relative to carrier strip 32 the ends 34 of the preform are rolled slightly asIiI- lustrated in FIG. 4. The preforr'n'is rolled a direction so that the burrs 22 on fingers: 16 will face the interior of the further tothe' configura tionillustrated' in FIG. '5. I
I At the sisthstation, rolling of the preform is'completed 'so that ends 34 abut each other at seam 36 and t h'e portion of the preform containing fingers is cylindrical. At the sixth station, as illustrated in FIG. 6, fingers l6remain located within the thickness of the preform 2G and burrs 22 on the fingers face the interior of the rolled preform.
Thefonnatio'n of eyelet '10 is completed at the seventh'sta tion where fingers 16 are bent into 1thefinterior-of the eyeletbody so that, illustrated in FIG. 7, the freeends 38 of the completed eyelet. At the station the preform 26 is rolled:
' fingers are grouped together. At. this time the portions of the eye euo between notches 30 may be bent inwardly toiprovide a rounded lead-in) to facilitate positioning of the eyelet within acircuitboar'd hole.
' As illustrated in FIG. 8 a circuit boardeyeletfl l o may be I severed from strip 32 and seated within 'holefQZ of circuit board 44, with lead-in 40 flared outwardly to secure'thee'ye'let within the hole. Upon insertion of a lead wire, 46' within the eyelet, fingers 16 are spread apart so that burrs 2:2 engage the parent as the description proceeds, especially when taken in conjunction with the accompanying drawings illustrating a preferred embodiment of the invention, wherein:-
FIG. I is a perspective view of the progression of a metal strip through a progressive die illustrating the formation of a circuit board eyelet according to the invention;
FIGS. 2, 3, 4, 5, 6 and 7 are sectional views takenrespectively along lines 22, 3-3, 4-4, 5 5, 6-6, and 77 of FICLI; and I FIG. 8 is a sectional view illustrating the use of a board eyelet according to the invention.
As illustrated in FIG. 1, circuit board eyelet circuit 10 formed wire. Movement ofthe wire past the'burrs causes the burrs to bite intothe wire so that the fingers grip thewire securely.,The burrs at the long edge 18 of the fingers are urged into'contact with a lead inserted into'eyelet- 10 and form a" locking grip on the lead'which'resists removal of the lead from the-eyelet. This is because the burrs cross the surface of the lead at an'acute angle. The burrs'at the free ends of the fingers also engage the lead.
In the manufacture of a conventional wire grip terminals,
" the fingers are punched from the stock in a' direction opposite from a strip of relatively thin sheet metal stock l2 which is 1 moved past a number of die stations. At each station a the pair performs an operation on the strip. The strip 12 may be made of brass suitably coated with solder or other metal. The strip is provided at regular intervals with pilot holes 14 which run the length of the strip and are used to assure proper orientation of the strip at each die station. The strip is'moved in the direction ofthe arrow in FIG. 1.
the direction in which fingers 16 are punched at the first posi- I tion of the progression illustrated in FIGS. 1 and 2 so that the wire grip fingers onthe completed terminal are not provided with wireor lead-engaging burrs facing into the body of the. terminal. Rather, the edges of the fingers facing the interioi of the terminalare rounded and do not bite into'the lead.
While I have'illustrated and described a preferfed .embediment of rny'invention, it is understood that' t hi's is eapable of modification, and I therefore do not wish to belimited'to the Precise details set fans. Y
WhatIclairjnas my invention is: I I I l. A 'wire grip terminal comprising a longitudinal hollow body,'at least one wire grip finger cut from the wall of said body and projecting into theinterior of said 'body, and a con- I tinuous wire grip b'urr on the corner of the finger facing the in- At the first station of the progressive die, four triangularly 4 shaped wire grip fingers 16 are punched from the. strip 12. Each finger is severed from the strip along the edges '18 and terior of the body extending from the junction of one side of the finger with the wall alongsaid side of the finger, past the tip of the finger and along the other side of the finger to the remains attached to the strip at connecting portion 20. The junction of said other side of the finger andthe wall.
7 together, a continuous burr extending fromthe wallalong both edges on said sides of the finger and around the apex of the finger.
3. A circuit board eyelet formed from relatively thin sheet metal stock comprising an elongate cylindrical hollow body rolled from said-stock, means at the ends of said body .for confining theeyelet within a circuit board hole, and a plurality of tapered wire grip fingers cut out from said body and bent into n the interior of said body with the ends of said fingers grouped together, and a burr extending from the wall along each side of each finger at the edge facing the interior of the body for engaging a lead inserted into said eyelet.