US 3730972 A
A wire-wrap terminal for a terminal pin for use with fine wire, in computer circuitry for example, is provided utilizing a pair of flat, juxtaposed, conductive extensions on one end of the pin to form a clamping interface. The extensions may be fabricated of the same electrically conductive metal sheet as the terminal pin with one of the extensions having portions cut away to form resilient prongs interfaced against a datum plate, being the other extension. The outer end of one of the extensions, such as the resilient prongs, is slightly bent outwardly for ease of insertion of the fine wire and at least one shoulder limits the depth of insertion. In making the wire-wrap, the wire is inserted between the interfacing extensions against the shoulder limit, wrapped around both extensions a plurality of times, preferably in a single layer, outwardly from the limit, thus constraining the extensions with the inserted portion therebetween, and again inserted into the clamping interface. The end of the wire may then be clipped or broken off against the edge of the datum plate. No strain or crimp is placed on the wire and no tools are required in making the wire-wrap.
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Description (OCR text may contain errors)
Unite States Patent 1 Hennessey WIRE-WRAP TERMINAL AND A METHOD OF MAKING A WIRE-WRAP CONNECTION Inventor: William M. Hennessey, Somerville,
Assignee: Burroughs Corporation, Detroit, Mich.
Filed: Mar. 20, 1972 Appl. No.: 236,306
US. Cl ..174/94 R, 29/628, 339/258 P,
[451 May 1, 1973 Primary Examiner-Bernard A. Gilheany Assistant Examiner-D. A. Tone Att0rneyCharles S. Hall [5 7 ABSTRACT A wire-wrap terminal for a terminal pin for use with fine wire, in computer circuitry for example, is provided utilizing a pair of flat, juxtaposed, conductive extensions on one end of the pin toforrn a clamping interface. The extensions may be fabricated of the same electrically conductive metal sheet as the terminal pin with one of the extensions having portions cut away to form resilient prongs interfaced against a datum plate, being the other extension. The outer end of one of the extensions, such as the resilient prongs, is slightly bent outwardly for ease of insertion of the fine wire and at least one shoulder limits the depth of insertion. In making the wire-wrap, the wire is inserted between the interfacing extensions against the shoulder limit, wrapped around both extensions a plurality of times, preferably in a single layer, outwardly from the limit, thus constraining the extensions with the inserted portion therebetween, and again inserted into the clamping interface. The end of the wire may then be clipped or broken off against the edge of the datum plate. No strain or crimp is placed on the wire and no tools are required in making the wire-wrap.
10 Claims, 5 Drawing Figures Paterit ed'i'Ma y 1, 1973 3,130,972
2 Sheets-Sheet 1 .HMHIH'HIZH :1. I
Patented vMany 1, 1973 2 Sheets-Sheet 2 1- WIRE-WRAP TERMINAL AND A METHOD OF MAKING A WIRE-WRAP CONNECTION BACKGROUND OF THE INVENTION The invention relates to an apparatus for connecting a fine signal-carrying wire, e.g. as those used in computer circuitry, to an electrical terminal socket and more particularly relates to a terminal pin, for mating with such a terminal socket, having extensions constructed so as to receive a wire-wrap connection.
In the field of making electrical connections between a signal-carrying wire and an electrical terminal socket it has been customary to use a terminal pin as an intermediary device to which the wire is attached by either soldering, crimping or wire-wrapping, then to insert this pin, which has either a male or female mating portion, into the corresponding mating portion of the electrical terminal socket. Another approach to making this electrical connection is to snap the terminal pin into the mating socket, first. The socket structure will then support the pin while the signal-carrying wire is attached to the specific portion of the pin designed to receive it, again by either soldering, crimping, or wirewrapping.
The use of soldering and wire-crimping is undesirable in some applications of computer wiring because the equipment involved to make the connection-is very often too bulky for the small spaceconstraints in which it must be used. On some occasions the connection must be made in the field where it is inconvenient to obtain a power source for soldering. In addition, soldering is undesirable in that the heat generated by a solder ing instrument could very often damage sensitive electronic components. Crimping is undesirable when fine wire is used because such crimping very often breaks the fine wire. V
For many such fine-wire connections in computer circuitry, a wire-wrap terminal pin is very desirable. In
the prior, art wire-wrap terminal connections usually required a wire-wrap tool tomake a sufficiently secure wire-wrap connection. A majority of these prior art devices have a straight shaft or pin of either circular, rectangular or triangular cross section. Regardless of the cross-sectional design of the pin the method of making a wire-wrap connection is the same, and a wirewrap tool is used. One end of the wire is held in position while a section of wire is wrapped around the pin, using the wire-wrap tool to perform the operation, so that the turns wind upon one another adding to the pressure of the wrap and securing the connection. A wire-wrap tool is essential when this type of pin is used in order to apply the pressure and control needed to produce the tightly wound wrapping necessary for a connection.
An object of this invention, therefore, is to provide a connecting intermediary between a fine wire and a terminal to which the connection can be made without soldering and without crimping the wire.
Another object is the provision of a terminal pin to which a fine wire-wrap connection may be made without the use ofa wire-wrap tool.
A further object of this invention is to provide a wirewrap terminal pin whose wire-receiving portion will securely hold the wire while a wrapping is made.
SUMMARY OF THE INVENTION The objectives of the invention are accomplished in a terminal pin, preferably fabricated from a single sheet of metal, by forming a pair of resilient interfaced clamping plates, having smooth juxtaposed surfaces, as extensions of the pin. To form the connection, the wire is first transversely inserted deeply between the interfaced plates, which are separable to receive the wire, then wrapped around both plates in a plurality of turns, preferably in a single layer, to increase the pressure'by whichthe plates bind the inserted portion of the wire, and again inserted between the clamped together resilient plates, the wrapping operation being entirely manual. One of the extension plates may be partially cut away, with respect to the other, for increased resiliency, and the outer end may be bent outwardly from the other for ease of insertion of the wire between the plates. A stop member may be provided to limit the depth of the original insertion of the wire between the plates.
DESCRIPTION OF THE DRAWINGS The various objects, advantages and features of this invention will become more fully apparent from the following detailed description, appended claims and accompanying drawings in which:
FIG. 1 is a plan view of a terminal pin including the wire-wrap terminal of the invention, constructed by stamping and forming a metal sheet.
FIG. 2 is an elevation view of the pin of FIG. 1 showing the wire-wrap terminal from the open side of the pm.
FIG. 3 is an elevation view of the pin of FIG. 1 showing the wire-wrap terminal from the closed side of the pin.
FIG. 4 is a perspective view of the pin of FIG. 1 showing the wire-wrap terminal with the wire wrap connection applied in the preferred configuration.
FIG. 5'is a perspective view of the pin of FIG. 1 showing a modified wire-wrap terminal of the invention with the wrap connection applied DETAILED DESCRIPTION OF THE INVENTION The wire-wrap terminal of the invention is preferably integral with a terminal pin, such as used for insertion in the back plane of a computer, and formed from a single stamping of sheet metal. In the illustrated embodiments (FIGS. 1,2,3) the wire-wrap terminal 11 is shown on the opposite end of a male terminal pin from a shaft portion 13, both being formed from the same metal stamping as the body portion 15.
Preferably the stamping is folded longitudinally in three sections so that the center section formsa side of the pin. The body 15 and shaft portion 13 of the illustrated pin, therefore, include a base 17, a closed side 19, and a top 21, the cross section of the body 15 and the shaft portion 13 being rectangular with one side 23 substantially open, and with the cross section of the shaft portion 13 preferably smaller than that of the body 15.
The elongated shaft portion 13 of the male terminal pin, for example, in which the invention may be utilized may have the outer end crimped inwardly to form a penetration end 25 and may have one or more corrugations 27 running longitudinally in the sides for increased strength.
The body of the terminal pin in whichthe invention may be utilized may have stopping surfaces 29,31 which limit the penetration of the terminal pin into a receptacle. A resilient detent 33 locks the pin in the receptacle once it is properly inserted, as known in the art.
It has been found that terminal pins in which the wire-wrap terminal of the invention has preferred utility give excellent results when fabricated from phosphor bronze sheet metal. Such sheet metal may be 0.005 inches thick and preplated with a tin solder coating substantially free of nicks and burrs, as known in the art.
In the preferred embodiment of the wire-wrap terminal of the invention the base 17 and top 21 of the body of the illustrated terminal pin have extensions 39,34 respectively, opposite the shaft portion 13 in the form of substantially rectangular plates. Preferably the extension 39 of the base 17 continues in the same plane as the base, forming a datum plate.
The extension 34 of the top 21 of the terminal pin, however, is bent downwardly at the end of the body portion 15 at a convenient angle, such as 30, to meet the datum plate 39 and again bent to form a plane parallel to and interfacing the datum plate. The extensions 39,34 may be, for example, two to three times as long as the width of the terminal pin, forming two resilient members with theirjuxtaposed surfaces free of nicks or burrs which might damage a fine wire inserted therebetween. I
Preferably the upper plate 34 of the wire wrap terminal has an elongated central portion parallel to the edges cut away to form a bifurcated plate of two prongs 35,37 of increased resiliency. The tips 41,43 of the prongs 35,37 may be bent outwardly from the datum plate 39 at any convenient angle, such as 45, forming a wedge or camming surface to facilitate the insertion of a wire between the plates 34,39.
In making the stamping for the pin and the wire-wrap terminal of the invention the center section of the stamping, forming the side 19 of the illustrated terminal pin terminates at the edge of the body portion 15 of the pm.
Two tabs 45,47 formed on the sides of the datum plate 39 are bent along the edges of the plate 34, the edges of the tabs outwardly from the body 15 of the ter minal pin being substantially aligned with the intersection of the two extensions 34,39. The tabs 45,47 are stop members for limiting the depth of the insertion of the signal-carrying wire during the making of the wirewrap connection. It is apparent that the depth of the insertion of the wire between the resilient plates 34,39 alternatively may be limited by a down-turned tab on the plate 34 or an up-turned tab on the plate 39, which alternative members could be located centrally in the plate.
A secure connection may be made to the wire-wrap terminal of the invention without the use of tools. A section of the wire is wedged laterally into the interface of the resilient plates 34,39 to abut against the stop members 45,47. The wedging surfaces of the up-turned tip of the upper plate 34 and the resiliency of the plates 34,39 facilitate the manual insertion of the wire without difficulty.
As previously stated the interfaced surfaces of the plates 34,39 must of course be free of nicks and burrs which might scratch, or even break, the inserted portion of the wire.
The clamping action of the resilient plates 34,39 holds the inserted portion of the 'wire 49 in position while the rest of the connection is made. In the preferred embodiment, FIG. 4, the upper plate 34 is in the form of two resilient prongs 35,37. The wire is then wrapped by hand in a plurality of turns, preferably in a single layer, outwardly from the inserted portion of the wire around both of the prongs 35,37 and lower plate 39.
The inserted portion of the wire 49 is thus tightly clamped in an excellent conductive connection between the extensions 34,39 of the terminal pin itself. In the preferred embodiment in the final turn the wire may be slid laterally between the prongs 35,37, being over one prong such as 35 and between the other prong 37 and the datum plate 39 (FIG. .4), or the wire may be slid laterally between both prongs 35,37 and the datum plate, to clamp the end of the wire section following the turns. v
In the alternative embodiment, FIG. 5, the upper plate 34 has not been bifurcated. In this embodiment the final turn of the wire is inserted between the upper and lower plates 34,39 to clamp the end of the wire section following the turns.
After the connection is made, excess wire may be clipped off, or it may be broken off against the edge of the datum plate 39.
What is claimed is:
1. In combination with an electrical terminal pin having at least a body portion, a wire-wrap terminal for manual connection of a wire comprising:
resilient, conductive clamping means, including a pair of opposed extensions of said body portion having interfaced planar surfaces for receiving a first transverse section of the wire wedgingly inserted therebetween, for further receiving around said opposed extensions a plurality of turns of the wire outwardly from said inserted section and said body portion of said pin for binding said inserted section of the wire between said planar surfaces, and for further wedgingly receiving between said planar surfaces a second transverse section of the wire outwardly from said plurality of turns.
2. The wire-wrap terminal of claim 1 further including stop means on one of said opposed extensions for limiting the depth of the insertion of said first transverse section of the wire.
3. The wire-wrap terminal of claim 1 wherein one of said opposed extensions includes bifurcated prong means for increasing the resiliency of the extension.
4. The wire-wrap terminal of claim 1 wherein the end of one of said opposed extensions outwardly from said body portion of said terminal pin includes camming means for facilitating the insertion of said wire.
5. A method of manually making an electrical connection by wrapping a wire around an electrical terminal having a pair of resilient conductive plates jux taposcd in a clamping interface comprising:
laterally inserting a section of the wire into the interface between the resilient conductive plates;
binding the plates against the inserted section with a series of turns of the portion of the wire immediately following said inserted section around said pair of plates and outwardly toward the point of insertion of said section; and
clamping the section of the wire immediately following said turns between said plates.
6. The method of claim 5 wherein the steps of inserting and clamping each includes the step of wedging said wire between said plates.
7. The method of claim 5 where the step of binding includes the step of winding said wire around said pair of plates in a single layer of turns.
8. The method of claim 5 wherein one of said resilient plates is bifurcated to form two resilient prongs and wherein said step of clamping includes the steps of:
continuing said series of turns across one of said prongs; and
wedging said wire between the other of said prongs and the other of said plates.
' 9. The method of claim 8 including the additional step of breaking off any balance of said wire against an edge of said other plate.
10. A wire-wrap connection for a wire-wrap terminal, having a pair of flat, smooth prongs in resilient contact with a smooth flat datum plate to form a clamping interface, and a stop member for limiting the depth of insertion of a wire into the clamping interface, which connection may be applied by hand comprising:
a first section of wire in said clamping interface between said pair of prongs and said datum plates abutted against said stop member;
an intermediate single layered wrapping of wire around said prongs and said datum plate extending outwardly from said stop member; and
a terminal section of wire in said clamping interface between at least one of said prongs and said datum plate.