Electrical contact

A micro-miniature electrical contact comprises a first contact portion having spaced cantilever contact leaves with distal ends adapted to mutually engage, together with outwardly bowed control longitudinal portions. When received in a mating socket the leaves are resiliently urged inwardly to effect desired receptacle engagement and electrical connection. In a preferred embodiment, the contact is formed by deep drawing a seamless, integral, generally cylindrical member in which a contact portion with leaves integrally joined at their distal ends is integrally formed with a receptacle portion adapted to engage an electrical conductor. Because of their construction, the provided contacts are adapted for repeated use without loss of resiliency.

This invention relates to multi-leaf and to slotted electrical contacts, 
and more particularly pertains to low-insertion force contacts adapted for 
repeated use without loss of contact efficiency. This application is a 
continuation-in-part of my copending application Ser. No. 566,595 filed 
Dec. 29, 1983. 
The development of computer technology has been accompanied by an attendant 
need for micro miniature contacts having low insertion forces for repeated 
connect-disconnect capabilities in receiving receptacles. Such contacts 
are employed in an ever-growing number of both civilian and military 
applications. Because of the tremendous numbers of such contacts which may 
be employed in a single installation, the need is also constantly growing 
for contacts which assure desired electrical communication while possessed 
of cycle durability and yet are of low cost. 
In accordance with this invention novel low-insertion-force pin contacts 
are provided which possess all of the above noted desiderata. The contact 
constructions hereinafter described are particularly adapted for micro 
miniature size manufacture without any loss of contact efficiency or 
reliability after repeated insertion and withdrawal relative to contact 
sockets employed in completing an electrical connection. 
One embodiment of the provided contact employs a multi-leaf contact portion 
integrally formed with a conductor receptacle or sleeve portion for 
securely engaging the end of an electrical conductor. The multi-leaf 
contact portion is adapted to inwardly resiliently flex in the course of 
insertion into the receptacle or socket of a mating connector element. 
A preferred embodiment of the provided contact employs a slotted tubular 
barrel member having deformable, leaf-like contact portions integrally 
formed at their distal-tip portions. Such contacts also comprise integral, 
conductor-receiving barrel portions from which such joined contact 
portions extend. The joined leaf-like portions are able to resiliently 
flex, and due to their end connection are reinforced against twisting 
relative to each other in the course of insertion and withdrawal relative 
to a receiving socket. 
The use of electrical contact having compliant insertable contact portions 
is well-known, as is the use of contacts requiring low insertion forces. 
Thus, Griffin U.S. Pat. No. 4,166,667 discloses a circuit board connector 
system employing contacts having barrel portions of C-shaped cross-section 
which deform in the course of being received in electrically conductive 
openings of a circuit board. 
Tamburro U.S. Pat. No. 4,076,356 discloses an interconnection pin for 
printed circuit boards having a compliant section of generally C-shaped 
sectional configuration with raised pressure ridges formed in the outer 
surface adapted to engage inner electrically conducting peripheries of 
circuit board openings in which received. 
Schramm U.S. Pat. No. 4,191,440 discloses an electrical connector for 
compiling leads to circuit boards employing pin contacts having compliant 
sections of C-shaped cross-section and tapered ends for reception in 
plated openings of circuit boards. 
Knowles U.S. Pat. No. 4,017,143 discloses a solderless electrical contact 
having a compressible, compliant barrel portion of C-shaped cross-section 
for reception in the plated openings of a circuit board. 
Kurtz et al. U.S. Pat. No. 3,783,433 discloses contacts similar to those 
disclosed in the Knowles patent but which have compliant barrel portions 
of various sectional configuration, as well as detents for locking said 
contacts in fixed position relative to a receiving circuit board. 
Gluntz U.S. Pat. No. 3,992,076 discloses a circuit board contact having 
cantilever spring arms which are insertable in the receiving openings of 
an insulating board. Solder is employed for effecting electrical contact 
between the contacts which are permanently set in place and a printed 
circuit on the surface of the board. The arms of the Gluntz contact are 
inadequate for providing the desired electrical contact and interlocking 
with the inner peripheries of the insulation board even were the latter 
peripheries coated with an electrical conducting material. There is no 
suggestion of contacts made in accordance with this invention in the 
Gluntz patent. 
Nijman U.S. Pat. No. 3,693,140 is of interest in that it discloses 
miniature electrical contacts having projecting tines separated by wide 
slots, the tines being formed of similar gauge or different gauge 
material. The contact of this reference requires a plurality of machining 
operations not necessary in the formation of the contacts of this 
invention. 
Plyler, U.S. Pat. No. 4,169,654 discloses a pin type electrical contact 
terminal formed of a slit sleeve. The open construction thereof does not 
provide the integrity present in the contacts hereinafter discussed. 
Lambert U.S. Pat. No. 4,437,726 discloses a flexible pin construction 
composed of opposed formed fingers 15 and 16. Such pins similarly to the 
above noted Plyler pin construction do not possess the integrity of the 
structure of the contacts hereinafter described in detail. 
German OS2514686 discloses a generally tubular pin contact requiring a 
large number of forming steps and of substantially semi-circular cross 
section along the major part of its length terminating at a sloping point 
for facilitating pin insertion. There is no suggestion of a cantilever 
leaf construction. 
U.K. Pat. Nos. 241,785, 367,267 and 1,088,235 disclose various forms of 
contact plugs having bendable leaves. However, the constructions disclosed 
are either formed of a plurality of parts or of massive construction 
resulting in an expense of manufacture rendering the same unsuitable for 
applications satisfied by the contacts of this invention. 
It is thus an object of this invention to provide an improved contact 
construction providing desired electrical contact with a mating socket and 
which provides redundant contact for desired electrical conductivity 
between the contact and socket defining an electrical connection. 
It is a further object of this invention to provide a novel micro miniature 
electrical contact of excellent cycle durability which requires low 
insertion forces while at the same time assuring a desired, secure 
engagement with a receiving socket. 
It is a further object of this invention to provide a novel one-piece 
unitary contact construction of micro miniature size employing resilient 
contact leaves integrally formed with and extending from a cylindrical 
barrel portion which securely engages an electrical conductor by means of 
a crimp engagement. 
It is another object of this invention to provide a one piece unitary 
contact construction employing resilient contact leaves integrally formed 
with a cylindrical barrel portion at their proximal end portions. The 
provided contact leaves are also joined at their distal terminal ends by 
means of an interconnecting portion rendering the contact more unitary in 
nature whereby the leaves are resistant to twisting relative to each 
other. Such latter contacts may also be micro-miniature in size. 
It is another object of this invention to provide a method for forming a 
novel contact construction by progressive drawing and slotting operations 
whereby contacts may be readily formed on a continuous basis from a thin 
sheet or strip of desired material of fabrication. 
It is yet another object of this invention to provide a method for forming 
a novel contact made in accordance with this invention by simple extrusion 
and slotting steps which enable the contacts to be manufactured in a rapid 
manner although possessing a precise uniform construction maintained 
within desired dimensional tolerances. 
It is yet another object of this invention to provide electrical contacts 
adapted for micro miniature use in which the contacts may be arranged in 
close-packed arrangement, as on centers of as little of 0.025 inch. 
It is another object of this invention to provide a novel multi-leaf 
contact which is readily adaptable for incorporation with a contact 
portion having a compliant section, whereby the resulting contact may be 
received in adjacent receptacle portions such as openings in adjacent 
printed circuit boards adapted to be electrically connected. 
The above and other objects of this invention will become more apparent 
from the following detailed description when read in the light of the 
accompanying drawing and appended claims. 
In one embodiment of the provided invention an integral cylindrical contact 
body is formed by extrusion. One end of the cylindrical body has 
longitudinal slots formed therein so as to form spaced cantilever arms or 
leaves. An endwise force is applied to the distal ends of such leaves so 
as to urge such ends together while simultaneously uniformly, outwardly 
bowing each of the central portions of such leaves. Such outwardly bent 
portions form a maximum leaf periphery adapted for insertion in a 
cylindrical socket or receptacle which is electrically conductive or has 
an electrically conductive inner periphery so as to effect an electrical 
connection therewith. Such socket is of smaller diameter than the diameter 
of the maximum periphery defined by the contact leaves so as to insure an 
efficient multi-point contact. 
The contact also employs a crimp barrel portion adapted to receive one end 
of an electrical conductor for secure engagement therewith. 
In a modified extruded contact construction, the integral barrel portion of 
the contact opposed to the leaves may be connected as by welding or the 
like to an elongate slotted male contact portion having a compliant center 
section. The resulting contact may be received at opposed ends in female 
receptacle portions for purposes of effecting two electrical connections 
as will hereinafter be disclosed in greater detail. 
In a further modified contact construction provided pursuant to this 
invention, an integral contact construction is formed by progressive deep 
drawing of a spinodal material or equivalent copper-based alloys having 
characteristics similar to those set forth in Unified Numbering System 
Standard No. 72900. The tubular formations drawn in such sheet material 
are slotted along opposed longitudinal edge portions so as to provide an 
integral, generally tubular body portion having spaced leaves separated by 
longitudinal slots. The leaves are joined at their proximal end portions 
with a cylindrical barrel portion adapted to receive a conductor. The 
leaves remain joined at their distal terminal ends following the slot 
formation, by means of an end connecting portion whereby a unitary contact 
construction results. The two leaves are bent outwardly by means of a 
force applied to the joined distal ends thereof so as to form a maximum 
leaf periphery insertable in a cylindrical, contact-receiving socket. The 
leaf maximum periphery is compliantly deformable in the course of engaging 
said socket assuring desired electrical contact. 
The latter contact construction having leaf distal ends integrally formed, 
may also be integrally joined with an elongate barrel portion. The latter 
defines a second male portion with a second compliant center section in 
the manner above indicated for the first modified contact construction. 
The second compliant section may thus be received in a female receptacle 
for purposes of effecting a desired electrical connection.

Referring more particularly to FIG. 6 a contact 10 made in accordance with 
this invention is illustrated having a multi-leaf contact portion 12 
adapted to be received in a female socket or receptacle 14. It will be 
noted from FIG. 6 that both the contact 10 and the socket 14 have integral 
barrel portions 16 and 18 respectively which are crimped to electrical 
conductors 41 extending through illustrated tubular insulating members 20. 
There may, of course, be applications in which the provided contacts 10 
and/or sockets 14 are employed in which the conductors are in an 
environment not requiring outer insulation, in which event the coverings 
20 may be eliminated. 
The leaved portion 12 of each contact 10 comprises a plurality of leaves or 
blades 22 which, are cantilever spring arms extending from adjacent an 
inner contact annulus 24. Annulus 24 interconnects the barrel or conductor 
receiving receptacle portion 6 and the contact portion 12. 
In accordance with one embodiment of this invention, each contact 10 
comprises an integral seamless element which is extruded from a slug of an 
electrically conducting material, such as slug 28 illustrated in FIG. 1. 
As a result of an extrusion step, extrusion 28A of FIG. 2 is formed having 
concentric and integrally formed tubular portions 16A and 12A from which 
the contact portions 16 and 12 of FIG. 6 are formed. 
Although the portions 16A and 12A are of different diameter as illustrated 
to accommodate a conductor for conductors of precise size at its barrel 
portion and to form spaced contacts 22 of desired peripheral arrangement 
at opposed end 12, a barrel of uniform diameter may be extruded from which 
contact portions 12 and 16 may be formed. Contact 10 is then formed by 
slotting the barrel portion 12a of the extruded element 28a of FIG. 2, 
resulting in the parallel leaves 22A of FIG. 3 separated by four slots 
30A, one of which is illustrated in side elevation. 
It will be noted from FIGS. 4 and 6 of the drawing that slots 30 which are 
formed in he completed contact 10 may vary in width with a resulting 
variance in the width of each of the leaves 22. Thus it will be noted that 
each slot 30 begins inwardly of each contact portion 12, extending from a 
curved periphery, widens in the course of progressing along the length of 
the contact barrel portion in which formed, whereafter the slot narrows 
upon approaching the distal end of the barrel portion 12. Each leaf 22 is 
thus seen to widen as it proceeds outwardly toward the distal contact end 
after which it will again taper upon approaching such distal end. 
Following slotting of the extrusion 28a of FIG. 2 resulting in the 
configuration of FIG. 3, die 32 having surface 34 and the distal ends of 
the spaced leaves 22A of FIG. 3 are moved into engagement. Following die 
engagement the slotted extrusion will become the completed contact 10 of 
FIG. 4 in which the distal ends of the four leaves are brought into mutual 
contact or closely spaced relationship (see FIG. 5). Simultaneously with 
the converging of the leaves by the die 32, the central portion of each 
leaf 22 will be bowed outwardly to form a maximum leaf circumference as 
represented by dotted line C of FIG. 6, which will effect contact with the 
inner periphery of a receiving socket or receptacle such as the socket 14 
of the drawing. 
FIG. 7 of the drawing illustrates the contact leaves 22 and socket 14 of 
FIG. 6 in the normal mated condition. A comparison of the positions of the 
leaves 22 in FIGS. 6 and 7 demonstrates the manner in which such leaves 
are inwardly resiliently flexed in the course of effecting contact with 
the inner periphery of the socket 14. It is apparent from FIG. 7 that each 
leaf 22 of contact portion 12 comprises in effect a cantilever spring arm 
touching at its outermost end with the adjacent leaves 22 at least during 
socket engagement, and extending at its inner end from adjacent annulus or 
periphery 24 with which each leaf is integrally formed. The leaves are 
thus seen to engage in a complementary, self-reinforcing engagement at 
their distal ends when in mating engagement with a socket. 
Each contact 10 is preferably formed of an extrudable, electrically 
conducting material such as a berylium copper alloy or a copper nickel tin 
alloy. Such alloys and alloys such as spinodal alloys are known in the art 
and provide desired electrical conductivity in addition to providing 
desired resiliency in each of the leaves or cantilever spring arms 22 of 
each contact 10. Because each leaf 22 is supported or in biasing 
engagement at opposed ends in the mated condition with the receiving 
socket as illustrated in FIG. 7, each leaf 22 is provided with a desired 
resistance to inward flexing as each leaf is formed to flex inwardly from 
its maximum periphery C illustrated in FIG. 6. FIG. 5 illustrates the 
adjacent relationship of distal ends of the leaves 22 in the normal 
position of rest as well as their complementary structural relationship. 
In accordance with this invention the leaf ends may be in mutual contact 
or slightly spaced apart in a position of rest. The normal gap between 
spaced leaf tips is of the order of a few thousandths of an inch. 
FIG. 7 illustrates the connection of a single contact and a mating socket. 
It is, of course, apparent to those skilled in the art that a plurality of 
such contacts and sockets may be mounted in electrically insulating 
housings for purposes of forming a multi-conductor connector. In FIG. 8 a 
plurality of electrical connections is simultaneously effected by mating 
housing 34 in which the female sockets 14 are mounted in aligned 
relationship with housing 36 in which the contacts 10 are correspondingly 
aligned. Latching members not illustrated but well-known in the art may be 
employed in conjunction with the housings 34 and 36 so that upon 
engagement of the lower surface of housing 34 and upper surface of housing 
36, not only are the contacts in desired electrical engagement with their 
associated mating sockets in the manner illustrated in FIG. 7 but, in 
addition, the housing members 34 and 36 are latched together. 
It will be appreciated by those skilled in the art that the arrangement of 
FIG. 8 is illustrative of one manner only of employing contacts made in 
accordance with this invention. The provided contacts may also be employed 
for purposes of effecting electrical communication as with a circuit on a 
PC board. The contact structure above described lends itself to ready 
incorporation in micro miniature applications, that is, for packaging in 
installations in which the contacts are packaged with in-line centers 
having as little as 0.1 inch spacing and diagonally arranged centers of 
about 0.005 inch spacing. 
It will be further appreciated that the contact embodiment 10 illustrated 
in the drawing utilizing four substantially parallel leaves 22 is provided 
by way of illustration only. A minimum of three discrete leaves are 
normally employed for purposes of assuring a stable interconnection with a 
receiving socket. 
However, by appropriate slot formation and size relationship between the 
contact and receptacle diameters stable surface-to-surface contact between 
each leaf and the receptacle results if a two-leaved contact is employed. 
In the contact embodiments of FIGS. 1 through 9, each leaf 22 provides a 
separate point of contact with the electrically conductive surface of its 
mating socket. Accordingly, the greater the number of leaves 22, the 
greater the number of electrical contacts. The provision of eight separate 
leaf members would provide eight separate points of contact; the possible 
number of leaves formed is dictated in part by the size of the original 
barrel which is slotted for leaf formation. 
It will be appreciated that the contacts of this application comprises most 
satisfactory substitutes for the more complex twist pin connectors of the 
type disclosed in Phillips U.S. Pat. Nos. 3,255,430 and 3,319,217. Methods 
of forming such pins are disclosed in Phillips Pat. No. 3,402,466. It will 
be noted that in forming these twist pins a plurality of wires are 
employed for conforming compliant male pin portions including seven outer 
wires wound about an inner core which may comprise one or more core wires. 
A typical twist pin construction is composed of eleven discrete elements. 
The plurality of elements and method of manufacturing such twist pins 
entail an expense which is approximately five times that of manufacturing 
the contact pins of this invention. 
It is apparent from the foregoing description that the provided contact 10 
of FIGS. 4 and 6, by employing a unitary extruded construction, has 
eliminated any seams which may comprise points of weakness in a formed 
contact. Such seams may separate after a crimping operation in which a 
barrel portion of the contact is crimped to an electrical conductor. By 
the utilization of the continuous barrel with integral cantilever leaf 
contact elements, a contact construction is provided possessed of 
excellent cycle durability. 
The basic structure provided readily lends itself to custom manufacture. 
Thus a number of leaves may be formed to provide the desired number of 
contacts with the female receptacle; it is contemplated that normally the 
number of leaves in the contacts of FIGS. 4 through 9 would comprise any 
number between 4 and 8, although 2 are also workable. 
The basic leaf construction provided in the above-described contact may be 
incorporated in a contact formed from rolled sheet material such as sheet 
segment 37 of FIG. 3A which has been predeterminately stamped or otherwise 
appropriately formed so as to form spring arms 39 separated by slots 41. 
Following rolling of the segment 37 into a cylindrical form the unslotted 
sheet portion may be crimped to conductors 41 extending from tubular 
insulator 20. The sheet portion may first be rolled into a cylindrical 
form prior to slotting. Such a rolled sheet will, of course, not have the 
unitary construction above described and would obviously be susceptible to 
separation along the seam. However, it is apparent that in certain 
applications crimping a contact to a conductor or conductor may serve to 
securely lock the contact to the encompassed conductor so that the danger 
of seam separation is extremely small or nonexistent when a multi-stranded 
conductor is crimped. However, when a solid conductor is employed, 
separation along the contact seam normally occurs with resulting poor 
electrical conductor-contact conductivity. Also, a separate manufacturing 
step may be employed to secure the seam-defining portions of the contact 
together. Contacts formed from such sheet construction would work to equal 
advantage with the contacts 10 illustrated in the drawing, and, the 
resulting contacts would look similar to contacts 10 but have a 
longitudinal seam. 
A modified contact construction 40 is illustrated in FIG. 9 wherein an 
upper contact portion 10B substantially identical to the contact 10 above 
described is formed integrally as by welding or the like at W, with a 
contact portion 42 having a compliant barrel portion 46. The barrel 
portion 46 has an elongate slot 48 which tapers at opposed longitudinal 
ends. In the normal course of utilization of the contact of FIG. 9, the 
contact portion 10B may be received in a socket in the manner above 
described, whereas the compliant barrel portion 46 may also be received in 
a female receptacle for purposes of effecting an electrical connection. 
Thus the contact illustrated in FIG. 9 has opposed male portions each of 
which is adapted to be received in a female receptacle. The contacts of 
FIG. 9 may serve many applications as, for instance, the connection of 
circuits on PC boards, barrel portion 46 illustrated in FIG. 9 being 
received in a plated through opening of a PC board 50. 
Another feature of the provided contacts which enables the same to be 
customized for particular uses comprises the ability to control the length 
of the slots 30 formed in an extruded cylindrical element or in a rolled 
sheet element for purposes of forming the spaced parallel leaves or spring 
arms 22. It is apparent that the longer the slots 30 the longer each 
cantilever spring leaf, and as a result such longer leaf is more 
susceptible to flexing upon receipt in a receiving socket. Accordingly, by 
shortening the length of the slots formed in a contact, the more resistant 
to bending the resulting leaves become. Thus, by regulating the lengths of 
the slots 30 a ready means is available for controlling the insertion 
forces necessary for effecting an interconnection with a mating receptacle 
element. The slots 30 need not extend the length of the contact portion 12 
as in the illustrated contact embodiment 10. 
A further modification of the provided contacts 10 comprises the flattening 
of one or more of the leaves 22 after formation. Such leaf flattening will 
result in contact being effected by each leaf along opposed longitudinal 
edges upon insertion in a cylindrical socket. FIG. 5A illustrates such a 
flat-leaved contact 10F. 
By way of example only, a contact above described and made in accordance 
with this invention may have the following dimensions. The contact, such 
as contact 10 illustrated in the drawing, may be formed from a 
copper-nickel-tin alloy and be approximately 0.005 inch in thickness. The 
contact may be approximately 1/4 inch in length with the leaf contact 
portion 12 and the barrel portion 16 each constituting approximately 
one-half of the overall length. The diameter of the maximum periphery 
formed in the bowed central portions of the leaves of such contact would 
be approximately 0.028 inch, and the diameter of the barrel portion 16 of 
such contact would be approximately 0.0375 inch. The terminal ends of the 
leaves of such a contact are in adjacent relationship at rest, i.e., 
either touching or have a gap therebetween of approximately 0.005 inch. 
The foregoing dimensions may, of course, be modified while still etaining 
the various inventive features above described in detail. 
FIG. 10 is a view similar to FIG. 6 and illustrates a preferred contact 
construction 51 which is formed as a result of a series of progressive 
deep drawing operations schematically illustrated in FIG. 15. In the 
course of such drawing operations a sheet of material 52 formed of a 
copper-nickel-tin spinodal alloy well known in the art is subjected to a 
progressive series of drawing steps in which punches 49 deform the sheet 
52 by forcing the same into underlying apertured dies 43. The provided 
sheet 52 may be of a thickness of the order of 0.004 inch and be in the 
form of an intermittently moving strip which successively engages each of 
a series of five drawing punches prior to entering a shearing station 
whereat a completely drawn contact body 51 A is sheared or punched free 
from the mother sheet 52, as seen in FIG. 15. The four punches 49 operable 
in forming the underlying metal deformations are of decreasing width and 
increasing length as the metal deformation progresses and sheet 52 is 
moved in the direction of the arrow as illustrated in FIG. 15. The punches 
49 and/or sheet 52 are appropriately lubricated as by spraying with a 
lubricating oil during the drawing operations in a manner well known in 
the art. 
At Station A of FIG. 15 a slight depression or dimple is made in the sheet 
52 of spinodal alloy by a reciprocating punch 49. At station B a further 
indentation is made by a punch and the metal is further drawn downwardly 
to form a cup-like depression. In station C a still closed longer tubular 
depression is formed as a third punch 49 draws the metal yet further 
downwardly. In station D the drawing is completed. In station E the 
finally drawn closed tube is engaged by opposed knife members K which 
skive material from oppositely disposed peripheral portions of the 
deformed metal, forming opposed slots 55 therein equivalent slotting 
apparatus known in the art may be employed for slot formation. Slots 55 
are more clearly seen in FIG. 11. In station F illustrated in FIG. 15, the 
contact 51A is sheared free from its connection to the mother sheet 52. 
The slots may be formed following shearing of the drawn tubular 
construction from the sheet. 
The drawn contact 51A will initially have an outer configuration as 
illustrated in FIG. 11. Contact barrel portion 54 is adapted to receive a 
conductor or conductors such as conductor 20 of FIG. 10 in the manner of 
contact 10 of FIG. 6. The initial contact form 51A further comprises an 
integrally formed, leaved portion 56 comprising joined, opposed leaves 58, 
see FIG. 11 which are spaced apart by slots 55. 
It will be noted from FIGS. 10 and 12 that each final contact form 51 
contains leaves 58 having outwardly bowed portions intermediate its 
opposed ends. The leaf proximal end portions are integrally formed and 
joined with the contact barrel portion 54 annulus 57, and the terminal end 
potions of the opposed leaves 58 extending from annulus 57 of each contact 
51 are jointed by an interconnecting portion 60 most clearly seen in FIG. 
13. The contact blank or form 51A subsequent to being sheared or punched 
from the sheet 52 is urged against a strike plate such as plate 62 
fragmentarily illustrated in FIG. 12 for purposes of having the bowed 
portions of maximum diameter 66 formed therein. The bowed portions 66 will 
then resiliently conform when inserted in the opening of a receiving 
receptacle such as socket 14 illustrated in FIG. 10. A strike plate such 
as plate 62 may be movable relative to the finally formed contact while 
still formed with sheet 52 of FIG. 15. 
The leaf-bearing steps schematically illustrated in FIG. 12 resulting in 
the bowed leaves in the contacts 51 also result in slots 55 with widths 
which conform with the degree of bowing in the sleaves defining the slots. 
Accordingly, the leaves of contacts 51 upon resilient flexing when 
engaging receiving receptacles may flex to the maximum degree where the 
slots are of maximum width. 
It is apparent from the foregoing description of contact 51 that the same 
comprises two opposed leaves 58 which are joined at their terminal ends by 
means of interconnecting contact portion 60 with which integrally formed. 
As a result, the leaves 58 are restrained from twisting relative to each 
other even when subjected to high insertion forces where received in a 
receptacle, and maintain a rigid unitary state in the normal course of 
use. 
By way of example only, the contacts 51 of FIGS. 10 through 15 may have the 
following dimensions. The two main segments of each contact 51, one 
segment comprising the leaved portion 56 and the second segment comprising 
barrel portion 54 may each be approximately 0.125 inch in length. Barrel 
portion 54 may have an average thickness of between 0.005 and 0.006 inch. 
The average outer diameter of the barrel portion 54 may be approximately 
0.035 inch plus or minus 0.002 inch. Base end portion B of contact 51 (see 
FIG. 11 may have a maximum diameter of approximately 0.04 inch and defines 
a reinforced funnel opening for reception of one or more conductors. The 
outer diameter of the smaller tubular portion 56 illustrated in FIG. 11 of 
the contact form 51A may be approximately 0.021 inch. 
Following engagement with a strike plate in the manner illustrated in FIG. 
12, the leaved portions 58 of the contact 50 will have a nominal diameter 
66 of approximately 0.0265 inch. The width of the leaf interconnecting 
portions 60 illustrated in FIG. 13 may be approximately 0.005 to 0.008 
inch. 
It is contemplated that microminiature contacts of this invention be 
received in receptacles having a diameter approximately 0.044 inch smaller 
in diameter. Thus contacts 51 of the aforenoted dimensions be received in 
sockets having a diameter of approximately 0.022 inch. 
The basic contact structure 51 illustrated in FIGS. 10 through 12 may be 
readily formed into a contact construction 51B such as illustrated in FIG. 
9 wherein the barrel portion 54 of contact 51B of FIG. 14 which is 
integrally formed with a contact portion 72 having a compliant barrel 
portion 76. The barrel portion 76 has an elongate slot 58 which it tapers 
at opposed longitudinal ends. In the normal course of utilization of the 
contact of FIG. 14, contact portion 56 may be received in a socket in the 
manner above described, whereas the compliant barrel portion 76 may be 
received in a receptacle for purposes of effecting an electrical 
connection. As a result, the provided contact construction of FIG. 14 may 
serve many applications as for instance the interconnection of circuits or 
elements on separate PC boards. Barrel portion 76 illustrated in FIG. 14 
is illustrated in electrical communication with a plated through opening 
in the PC board 50. The slotted barrel portion 76 of contact 51B 
illustrated in FIG. 14 may have all the functions and advantages of the 
comparable barrel portion 46 of the contact 40 illustrated in FIG. 9 and 
may be similarly modified so as to provide customized engagement. It 
should be noted that the extruded contacts 10 above described have a 
length to width ratio of less than 5. Accordingly, the contact 4 of FIG. 9 
must be formed of two separate pieces joined at W by welding or the like. 
By employing the deep drawing process above described in forming contacts 
51, and 51B of FIG. 14, such contacts may be formed from a single integral 
cup or close-ended tubular member without the necessity of joining a 
plurality of contact elements as by welding or the like. Contacts formed 
in accordance with the deep drawing steps above disclosed may have a 
length to width ratio of as large as 10-1. The drawn two-leaved contact 51 
is provided by way of example only and contacts with three and more leaves 
are also contemplated as within the scope of this invention. Both contacts 
51 and 10 may be of substantially uniform diameter along their lengths. 
Also, the deep drawing formation techniques allow the formation of even 
smaller contact sizes. Thus, drawn contacts may be mounted on in-line 
centers which are spaced apart as little as 0.05 inch and may be mounted 
on diagonally aligned centers which are spaced apart 0.025 inch. 
The process steps of extrusion and deep drawing above described may result 
in working hardening of the metal of the contacts formed. Appropriate heat 
treatments known in the art may be employed to provide the contacts with 
the desired ductility and resilience necessary for being secured to an 
electrical conductor and for engaging a mating receptacle. 
It is thus seen that a micro miniature contact has been provided 
particularly adapted for use in those installations where extremely large 
numbers of contacts are required and miniature size is a necessity. 
Exemplary uses are in computer installations for both civilian and 
military use. The provided contacts of the various embodiments illustrated 
in the drawings of this case may be readily made and provide repeated 
connect and disconnect operation without loss of resiliency. The provided 
contacts are less expensive to manufacture than the twisted wire and 
machined contacts of the prior art which had heretofore been employed in 
micro miniature applications such as those served by the contacts of this 
application. The provided contacts are inexpensive to manufacture and may 
be manufactured with a minimum number of processing steps. The processing 
steps are both technically simple and economical to carry out. 
It is believed that the foregoing description has made apparent a number of 
modifications which may be made in the invention disclosed without 
departing from the ambit thereof. Accordingly this invention is to be 
limited only by the scope of the appended claims.