U.S. patent number 3,757,284 [Application Number 05/240,532] was granted by the patent office on 1973-09-04 for socket type contact terminal.
Invention is credited to William G. Klehm, Jr..
United States Patent |
3,757,284 |
Klehm, Jr. |
September 4, 1973 |
SOCKET TYPE CONTACT TERMINAL
Abstract
A contact terminal of the socket type preferably formed from
sheet metal stock in which the socket portion thereof is folded
into channel formation to provide two side walls each similarly
longitudinally bowed toward one another to bring their respective
midsections into juxtaposition. Each side wall is dimpled in its
midsection to form an inwardly directed protrusion which is in
offset relation to the protrusion of the other side wall, the two
protrusions extending across the space between the midsections and
cooperating therewith to provide a constricted passage for
receiving a contact member introduced therebetween. With this
construction the gripping forces applied by the midsections of the
two side walls are substantially greater than the forces opposing
the introduction of a contact member therebetween, the gripping
forces in the region of the midsections acting perpendicularly to
the axial dimension of the socket and applying a squeezing pressure
considerably greater than the force required to insert and withdraw
the contact member, thereby preventing the latter from buckling
when introduced thereinto.
Inventors: |
Klehm, Jr.; William G.
(Farmington, MI) |
Family
ID: |
22906923 |
Appl.
No.: |
05/240,532 |
Filed: |
April 3, 1972 |
Current U.S.
Class: |
439/842;
439/873 |
Current CPC
Class: |
H01R
13/11 (20130101); H01R 12/58 (20130101); H05K
7/1038 (20130101) |
Current International
Class: |
H01R
13/11 (20060101); H05K 7/10 (20060101); H01r
011/22 () |
Field of
Search: |
;339/17R,17CF,17C,217R,221R,256S,256SP,258P,258F,258S,258R,252P,259 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Champion; Marvin A.
Assistant Examiner: Pate, III; William F.
Claims
What is claimed is:
1. An electrical connector assembly including, in combination:
a socket member in the form of a U-shaped channel of resilient
metal to be received in a throughway of a supporting electrically
insulating receptacle, the base of the channel being omitted from
the side walls along an intermediate portion of the length of the
member, thus leaving a pair of spaced webs along the base of the
channel between said side walls, the side walls of the channel
being bowed inwardly along said intermediate portion and providing,
within the channel shape, converging contact surfaces,
a contact terminal member of thin blade-shaped formation insertable
lengthwise into the mouth of the socket member formed at one end
thereof,
similar rounded protrusions bulged out from at least one inner face
of said bowed side walls and disposed in offset relation to one
another for guidingly engaging the leading end of the terminal
member introduced into the mouth of the socket member, said
protrusions being located midway of the length of said bowed side
walls and on opposite sides of the longitudinal axis of the socket
member of the connector, and
said protrusions acting to space the bowed side walls from one
another and cooperating therewith to form a narrow opening having a
longitudinal dimension approximating the width of the contact
terminal member insertable thereinto and a transverse dimension
aproximately half the thickness of such contact member.
2. An electrical socket for receiving a contact member and
comprising a sheet metal socket made from a single blank
longitudinally folded to provide a channel-shaped formation
comprised of a base and a pair of side walls, said socket having a
struck-out section along the base which terminates short of the
upper and lower ends of the socket to form upper and lower
connecting webs integrally joined to the side walls,
said pair of side walls being bowed inwardly toward one another to
bring their respective midsections into juxtaposition, the
midsection of each of said side walls being dimpled to form an
inwardly directed protrusion which is offset in laterally displaced
relation to the similar protrusion formed on the other side wall of
the socket,
one such protrusion being located at the inner edge of its side
wall formed by the struck-out section of the socket and such other
protrusion being located at the opposite outer edge of its side
wall, the two protrusions cooperating with one another in the
operating condition of the socket to maintain the midsections of
said pair of side walls in slightly spaced apart parallel relation
to one another, and
said protrusions being rounded to engage the side edges of an
introduced mating contact member and guide the same
therebetween.
3. A contact terminal of the socket type having a folded section
exhibiting an open-ended channel shaped formation thereby to
provide a pair of confronting side walls, the side walls being
bowed inwardly toward one another to bring the midsections thereof
into juxtaposition, and protrusions carried on the midsection of at
least one of said side walls and extending toward the other side
wall, said protrusions being laterally spaced apart sufficiently to
permit the passage of a contact member therebetween which is
introduced through the open end of the channel formed by the pair
of side walls,
said bowed side walls being resiliently arched toward one another
but being maintained in spaced-apart relationship by the abutment
of each protrusion against the side wall opposite to that upon
which it is carried.
4. The contact terminal as recited in claim 3 wherein the
protrusions are generally conically shaped and integrally joined at
their bases to the side wall upon which they are carried.
5. The contact terminal as recited in claim 4 whrein the
protrusions are displaced from one another transversely of the
longitudinal dimension of the side walls and cooperate with one
another and the side walls to form a narrow gap for receiving a
mating contact member introduced into the channel of the contact
terminal.
6. An electrical socket-type connector having the socket thereof in
the form of a channel of electrically conductive resilient material
adapted to be received in a cavity of a supporting receptacle of
electrically insulating material, the base of the channel being
omitted from the side walls along an intermediate portion of the
length of the member thus leaving a pair of spaced webs along the
base of the channel between said side walls, the side walls of the
socket between said pair of spaced webs being resiliently arched
toward one another inwardly along said intermediate portion and
providing, within the channel shape, converging contact surfaces
for guiding a contact terminal member inserted lengthwise into the
mouth of the socket formed at one end thereof,
similarly shaped protrusions carried on the inner face of the
midsection of at least one of said bowed side walls and disposed in
offset relation to one another transverse to and on opposite sides
of the longitudinal axis of the channel of the socket, the
protrusions each forming an integral part of the side wall on which
it is carried and being formed by a deformation of each side wall
from its initial flat condition,
said protrusions being cooperable with the side walls to form a
narrow opening extending crosswise to the longitudinal axis of the
socket for receiving a contact terminal member introduced into the
mouth of the socket, said protrusions being rounded on the sides
thereof facing one another and cooperating with one another to
engage the leading end of the contact terminal member introduced
into the mouth of the socket to guide the same therebetween.
Description
CROSS REFERENCE TO A RELATED APPLICATION FOR PATENT
Reference is made to applicant's copending application for patent
identified as Ser. No. 194,396, now U.S. Pat. No. 3,693,131 filed
Nov. 1, 1971, and entitled a PROGRAMMABLE DUAL-IN-LINE PIN
CONNECTOR FOR INTEGRATED CIRCUIT UNITS where the pin and socket
connector illustrated in FIG. 1 herein is shown but not claimed in
the aforesaid copending application.
FIELD OF THE INVENTION
The invention relates generally to integrated circuit components
and more particularly to a socket type connector for use in such
art.
BACKGROUND OF THE INVENTION
Electrical connectors having socket type sections for receiving and
gripping a mating electrical contact member are of common knowledge
and in widespread use. One of the problems associated with such
connectors is the difficulty encountered in inserting the mating
contact member and especially if it is of the thin blade type
associated with integrated circuit units. Contact blades of this
type are quite fragile and are likely to buckle as they are forced
into the socket of the connector, and attempts to reduce the
resistance to insertion also diminishes the gripping forces applied
to complete the electrical connection. In view of these
difficulties and problems, it is evident that an improvement is
needed which will minimize the resistance to insertion on the one
hand and increase the gripping forces providing the electrical
connection on the other hand.
SUMMARY OF THE INVENTION
It is accordingly an important object of the present invention to
provide an improved socket type electrical connector for use with
integrated circuit units and the like and so designed as to provide
a substantially higher force for gripping an introduced contact
member as compared with the force required to introduce such
contact member thereinto.
Another important object of the invention is to provide an improved
electrical socket type connector which is so constructed as to
provide a gradually converging mouth leading to a constricted
midsection area where counteracting forces grip an introduced
contact member with substantially greater forces than those
required for its introduction.
A further important object of the invention is to provide an
improved electrical connector of the socket type which can be
economically produced from flat metal stock to provide the
aforesaid advantages.
In carrying out the objects of this invention, the electrical
connector is so designed that when folded from a flat metal blank
into a channel formation and the side walls thereof are further
deformed toward one another there is produced an outwardly flaring
mouth for guiding a contact member thereinto and a middle channel
region which exerts a compressive force on a contact member
introduced thereinto of a magnitude substantially greater than that
required for the insertion of the contact member. To this end, the
side walls of the socket are inwardly bowed to bring their
respective midsections into juxtaposition and such midsections are
provided with inwardly directed protrusions which extend across the
space between the midsections and are disposed in offset relation
to one another to provide the constricted passage into which the
inserted contact member is received and gripped.
These and other objects, advantages and meritorious features of the
invention will become more fully apparent from the following
specification, appended claims and the accompanying sheets of
drawings wherein:
BRIEF DESCRIPTION OF THE DRAWING FIGURES:
FIG. 1 is a perspective view of one embodiment of a pin and socket
connector constructed in accordance with the present invention and
illustrating its folded condition prior to inclusion in an
integrated circuit unit;
FIG. 2 is a cross sectional view through an integrated circuit
block of insulating material in the cavities of which connectors of
the type illustrated in FIG. 1 are received and showing the
reception of a lead from an integrated circuit unit in one of such
connectors;
FIG. 3 is an end view of the socket portion of the connector of
FIG. 1 taken along line 3--3 of the latter;
FIG. 4 is a sectional view taken along line 4--4 of FIG. 3;
FIG. 5 is a plan view illustrating the flat metal blank prior to
the folding thereof to form the connector shown in FIG. 1;
FIG. 6 is a side view of the connector following the folding of the
blank of FIG. 5;
FIG. 7 is a side view of the connector of FIGS. 1 and 6 after the
connector is received in a cavity of the insulating block;
FIGS. 8, 9 and 10 are cross sectional views of the contact terminal
taken along lines 8--8, 9--9, and 10--10 of FIG. 7 and illustrating
the positions assumed the parts intersected by such lines when the
terminal is installed in a cavity of a connector block;
FIG. 11 is a side elevation of an alternative form of contact
terminal embodying the invention showing the same installed in a
cavity of a block of insulating material;
FIG. 12 is a side elevation of the contact terminal of FIG. 11 but
taken at an angle 90.degree. therefrom;
FIG. 13 is a cross sectional view taken along line 13--13 of FIG.
11;
FIG. 14 is a cross sectional view taken along line 14--14 of FIG.
11; and
FIG. 15 is a fragmentary perspective view of the entrance portion
of a cavity in the insulating block shaped to receive the contact
terminal of the character illustrated in FIGS. 11 and 12.
DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION
An electrical contact terminal constructed in accordance with this
invention is illustrated in FIG. 1. Preferably, the terminal 20 is
formed out of flat stock composed of electrically conductive
material and folded upon itself, thereby to exhibit two main
longitudinal sections, a channel-shaped, lead gripping portion
generally indicated at 22 and a cylindrical post portion generally
indicated at 24. The contact terminal is preferably manufactured by
stamping and forming operations and in the process of its formation
the base of the channel shaped portion is cut away as at 26 to form
a longitudinal opening occupying most of the base of the
channel-shaped socket as indicated in FIG. 6 and the post portion
24 is rolled upon itself sufficiently to bring the opposite edges
into substantial abutment to form a sleeve 28 having a seam
indicated at 30 in FIG. 6. In a typical use, the folded section 22
of the terminal is fitted into a recess or cavity 32 of an
electrically insulating body such as the hardened plastic block 34
illustrated in cross section in FIG. 2. The cylindrical post
section 24 will project beyond the block 34 for entrance into a
complementary contact socket (not shown) which may be formed in a
printed circuit board for this purpose.
The upper end of the folded section 22 of the terminal aligns
itself with the upper narrower end of the cavity 32 in the block 34
into which it is fitted so that a mating contact member 36 may be
slidably introduced thereinto as shown in the left cavity 32 of
FIG. 2. As the socket section 22 of the terminal 20 is introduced
and fitted into its cavity 32 its shape is further modified by the
walls of the cavity. In its initial form illustrated in FIGS. 1 and
6 the channel-shaped socket section 22 of the presently described
embodiment of the invention has two slightly diverging side walls
38 and 40. When the contact terminal is introduced into its
selected cavity 32 of the insulated block 34, the walls of the
cavity are so designed as to force the side walls of the socket 22
inwardly toward one another to assume in its final disposition in
the cavity a substantially parallel relation to one another. When
fully installed in the block, as illustrated by the left cavity 32
of FIG. 2, a thin strip lead or blade 36 from an integrated circuit
unit 42 may be introduced into the socket section 22 through the
upper opened end thereof and sufficiently far enough to be
grippingly engaged by the middle portion of the socket section
22.
A general description of one embodiment of the invention and a
particular use thereof has been made. Other details of this
embodiment will now be described with respect to FIGS. 6 and 10
inclusive. The initial fold of the socket section 22 produces a
channel formation consisting of a base and the two diverging side
walls 38 and 40 as previously mentioned. Moreover, the initial
struck out area 26 of the blank illustrated in FIG. 5 produces a
slightly converging but generally rectangular opening 26 in the
base of the channel as illustrated in FIGS. 1 and 6. The cutaway
area 26 extends for the major part of the socket section 22 but
terminates short of the upper and lower ends of the socket section
to form upper and lower connecting webs 44 and 46 respectively
which form parts of the original base of the channel and are
integrally joined to the side walls 38 and 40 as is evident in
FIGS. 1 and 6.
The two side walls 38 and 40 of the contact terminal are also
initially shaped at the time of fabrication so as to bring their
respective middle portions into juxtaposition as shown in FIGS. 1
and 6. The result of such a bending of the side walls 38 and 40 is
to impart an inwardly bowed condition to each wall bringing the
midsection 48 and 50 of each wall 38 and 40 closer together than
any other portion of the walls as is evident in FIG. 6. The
additional folding of the socket section 22 upon itself when
installed in operating condition in a cavity of an insulated body
such as 34 will force the midsections 48 and 50 closer together and
to assume a slightly spaced apart parallel relationship as
illustrated in the sectional view of FIG. 8.
One important feature of the invention is the provision of inwardly
directed bulges or protrusions formed on the inner surfaces of the
side walls 38 and 40 and particularly in the region of their
midsections 48 and 50 respectively. One such protrusion on
midsection 48 is indicated at 52 and a protrusion on the other
midsection 50 is indicated at 54. As illustrated in FIG. 5, these
two protrusions are preferably formed on the blank prior to the
folding thereof into the shape illustrated in FIG. 6, the two
protrusions being indicated in FIG. 5 by the same reference numbers
52 and 54 as appears in FIG. 6.
It should be further noted that the two protrusions 52 and 54 are
not directly opposed to one another but instead are located on
their respective midsections of the side walls 38 and 40 so that
they are offset from one another and preferably laterally of the
whole contact terminal 20 and on opposite sides of its longitudinal
axis. Also, it should be noted that each such protrusion 52 and 54
is located along an edge portion of the side wall, one on the inner
edge of the side wall 38 formed by the cutaway area 26 and the
other on the outer edge of the side wall 40. Furthermore, each
protrusion is generally conically shaped except that by virtue of
its location on the edge of its associated side wall in the
presently described embodiment its base does not occupy a full
circle. The result is that when the contact terminal is further
folded upon itself, as when placed in a cavity of an insulated
block designed to receive the same, the two protrusions are located
at the opposite ends of a narrow passage 56, as illustrated in FIG.
8, into which the outer end portion of a lead or blade 36 will be
received and gripped by the side wall midsections when fully
introduced thereinto.
In the presently described embodiment of the invention, the channel
formation of the contact terminal 20 is formed by bending the same
on two pairs of fold lines. One pair of fold lines is illustrated
at the upper end of the blank in FIG. 5 and identified by the
reference character 58, and the other pair is shown at the lower
end of the opening 26 in the blank by the reference character 60.
The fold lines of each pair extend parallel to one another but it
is evident from a comparison of the two pairs of such lines in FIG.
5 that the distance separating the fold lines of pair 58 is smaller
than that of the pair 60 with the consequence that the connecting
webs 44 and 46 are unequal in lateral extent as is evident in FIGS.
1 and 6. The result is that the overall formation of the socket
section 22 of the contact terminal 20 has a slight convergence from
the cylindrical post section 24 to its opposite end, thereby
assisting in its insertion in a selected throughway or cavity 32 of
the insulating block 34. It is also evident in FIG. 2 that each
cavity 32 gradually diminishes in cross section upwardly from the
base of the insulating block so that when the socket section 22 is
introduced thereinto its side walls are progressively bent toward
one another, eventually to bring the midsections 48 and 50 thereof
into the slightly spaced apart parallel relation exhibited in FIG.
8. FIGS. 9 and 10 also illustrate the parallel relation of other
portions of the side walls of the socket section after the same has
been fully received in a cavity 32 of an insulating block
dimensioned to receive the same and perform this function.
FIGS. 11 to 15 illustrate a modification of the invention wherein
in lieu of utilizing the interior formation of the cavity in which
the contact terminal is received to bring the side walls into
parallel relationship, the contact terminal itself is initially
formed to provide and maintain this parallel relationship prior to
insertion in a cavity. With more specific reference to FIGS. 11 to
15, the contact terminal 62 of this modification is generally
similar to that of the first described embodiment of the invention
including a socket section 64 joined to a cylindrical post section
65, both of which may be formed and shaped from a blank of flat
stock metal as previously described in connection with the first
modification of the invention. The socket section 64 is composed of
a pair of side walls 66 and 68 which are generally similarly shaped
with respect to one another and are inwardly bowed toward one
another as shown in FIG. 11 to bring their respective mid portions
into juxtaposition as is evident from FIG. 14. The midsection of
each side wall is provided with a bulge or protrusion which
projects toward the other side wall for contact therewith, but as
in the case of the first described embodiment the two protrusions
are offset laterally with respect to one another to provide a
narrow passage for receiving a mating contact member 36. The
protrusion associated with the side wall 66 is indicated at 70, and
similarly the protrusion carried by the side wall 68 is indicated
at 72. The cylindrical post section 66, however, is formed of two
complementary half sections having two substantially abutting seams
74.
It is evident from the several Figures illustrating the second
embodiment of the invention that the two side walls 66 and 68 of
the socket section 64 terminate differently at their upper and
lower ends from the embodiment previously described. In the
presently described form of the invention, the upper ends of the
two side walls are reversely bent upon themselves to provide, as in
the case of the side wall 66, a downwardly extending portion 76 and
likewise in the case of the side wall 68 a downwardly extending
portion 78. Integrally joined to these downwardly directed
extensions 76 and 78 are connecting bands or webs 80 and 82 as
shown in FIG. 14 which together with the downwardly turned
extensions 76 and 78 encircle the upper end of the socket section
as illustrated in this figure. Moreover, one of the webs, such as
80, has a greater length than its complementary web 82. The
terminal portion 84 of the longer web 80 is folded about the
downward extension 78 of the side wall 68 as shown in FIGS. 12 and
14. Constructed in this fashion, the upper end of this socket is
thus enclosed within a ring formed by the downward extensions 76
and 78 of the side walls and the web connections 80 and 82 with the
consequence that this end portion of the socket is restrained from
changing its shape and especially by any outward displacement of
the side walls away from one another which would adversely affect
the squeezing pressure exerted by their midsections on an
introduced contact member 36.
The lower end of the socket section 64 of the contact terminal 62
is generally similarly formed like the upper end previously
described. Each side wall 66 and 68 is integrally connected to the
other at the lower end of the socket section by a connecting band
or web 86 and 88 as illustrated in FIG. 13. One of these webs, such
as that identified at 88, extends longer than the other and is bent
to overlap upon the base of the side wall 68 as indicated in FIG.
13 by the reference character 90. Shaped in this fashion, the lower
end of the socket section is encircled by a ring formed by the web
extensions 86 and 88 and the overlapping portion 90 to hold the
base ends of the side walls from any outward displacement that may
occur which would adversely effect the squeezing pressure exerted
by their midsections upon an introduced contact member represented
at 36.
In addition to displaying a side elevation of the contact terminal
62. FIG. 11 shows the mounting thereof in a throughway or cavity 92
of an insulating block 94 which may be formed of hardened plastic
material. In such a mounting arrangement, the cavity 92 may be
approximately rectangular in shape as illustrated in the sectional
view of FIG. 15 and having a slightly wider dimension in one
direction at its lower end to accept the lower wider end of the
socket. To accommodate the overlapping portions 84 and 90
associated with the upper and lower ends of the socket section, the
cavity is provided with a corner groove 96 running the length
thereof and being of such a dimension as to accept the width and
depth of the overlapping portions as is evident by the dotted
representation of the groove in FIG. 11. The upper end of the
cavity 92 is provided with a reduced opening or mouth 98 formed in
the plastic body into which the mating contact member 36 is
initially introduced before entering the mouth of the socket
section 64.
Both embodiments of the invention employ chamfered projections or
lances to assist in holding the socket section of the connectors
against accidental separation from the cavities of the plastic body
into which they are inserted. In the first described embodiment of
the invention, such projections are illustrated at 100 and 102 in
FIGS. 1 and 3. In the second described embodiment, such lances are
illustrated at 104 at the base portion of the socket section
64.
In the operation of the two embodiments of the invention, it is
evident that upon introduction of a mating contact member 36, into
the socket 64, the thickness of the contact member is greater than
the distance separating the middle portions of the inwardly bowed
side walls of the socket. The usual practice at the present time is
to make the leads of the integrated circuit units of a thickness of
10 mils. Accordingly, to gain the desired results with the use of
the present invention, the minimal separation of the two side walls
of either embodiment is a distance of 5 mils, the offset
protrusions in either case acting to maintain this minimal
distance. The result is that when the contact lead or blade 36 of
an integrated circuit unit is projected into the midsection of the
socket of either embodiment, it will deflect the midsections of the
side walls away from one another by approximately 21/2 mils. Each
side wall may be considered as a simple supported beam held from
outward deflection at its opposite ends while the middle portion of
its arched configuration is capable of being deflected in an
outward direction by the introduced lead 36. Supported in this
fashion, each beam furnishes a substantially greater resistance to
outward deflection than would a cantilever type supported beam.
Performing in this manner, the two side walls 38 and 40 of the
first embodiment and the side walls 66 and 68 of the second
embodiment may be constructed to exert a pressure at their
respective midsections of from 200 to 400 grams in the direction
toward one another and perpendicular to the path of travel of an
inserted lead 36. This squeezing pressure on the lead is
substantially greater than such gripping pressures heretofore
employed for such type of connectors, the latter usually being in
the range of 30 to 50 grams. Moreover, it is evident that the bowed
side walls of either embodiment provide a gradually converging path
for guiding the inserted lead 36 to the midsection thereof. In the
presently disclosed embodiments of the invention, the entering lead
36 engages the side walls of the socket for a distance of
approximately 50 mils before the narrow midsection of the socket is
reached during which time the lead gradually wedges each side wall
a distance of approximately 21/2 mils. This mechanical advantage of
about 20 to 1 enables the lead introducing forces to be
substantially less than the gripping forces applied by the
midsections of the side wall on the introduced contact member, thus
preventing the leads from being deformed or buckled as they are
advanced into the sockets.
As previously mentioned, the inwardly directed protrusions 52-54
and 70-72 serve to provide and maintain the minimal distance
separating the midsections of the side walls of the socket, this
distance preferably being about one-half the thickness of the
introduced contact member. In addition, these protrusions are
laterally spaced apart from one another and function to engage the
opposite sides of an introduced lead 36 and guide the same
centrally, longitudinally of the side walls. To this end, the
rounded bases of the protrusions act to funnel the advancing end of
the lead therebetween and thus prevent the lead from straying
aside.
While two particular embodiments of the invention have been shown
and described, it will be understood, of course, that it is not
desired that the invention be limited thereto since modifications
may be made, and it is, therefore, contemplated by the appended
claims to cover any such modifications as fall within the true
spirit and scope of the invention.
* * * * *