U.S. patent number 3,851,297 [Application Number 05/364,851] was granted by the patent office on 1974-11-26 for substrate connector.
This patent grant is currently assigned to AMP Incorporated. Invention is credited to Geoffrey Hector James Munro.
United States Patent |
3,851,297 |
Munro |
November 26, 1974 |
SUBSTRATE CONNECTOR
Abstract
The invention concerns connectors having an elongate spring body
of elastomer or formed as a tubular spring about which a single
layer wire coil is wound. The coil turns are separated by cutting
the coil longitudinally of the body to define discrete conductive
paths of C-shape extending round part of the circumferential
profile of the body. Exposed surface portions of the wires present
contact points in a row along the body. Each C-shaped turn may
present a pair of diametrically opposite contacts. The coil may be
wound about a former disposed beside the spring body so that on
cutting the turn portions at the former leads to the individual
C-shaped turn portions extend freely from the spring body.
Inventors: |
Munro; Geoffrey Hector James
(St. Pierre Du Bois, GC) |
Assignee: |
AMP Incorporated (Harrisburg,
PA)
|
Family
ID: |
10276361 |
Appl.
No.: |
05/364,851 |
Filed: |
May 29, 1973 |
Foreign Application Priority Data
|
|
|
|
|
Jun 17, 1972 [GB] |
|
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28483/72 |
|
Current U.S.
Class: |
439/591; 439/66;
439/723; 439/637; 439/787 |
Current CPC
Class: |
H01R
12/79 (20130101); H01R 13/33 (20130101); H01R
12/7082 (20130101); H01R 12/87 (20130101) |
Current International
Class: |
H01R
12/16 (20060101); H01R 13/02 (20060101); H01R
12/00 (20060101); H01R 13/33 (20060101); H05k
001/07 () |
Field of
Search: |
;339/17,61,59,75MP,176MF,176MP |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
Dunman, "Printed Circuit Connector" IBM Technical Disclosure
Bulletin, Vol. 7 No. 3, page 182, August 1964..
|
Primary Examiner: Frazier; Roy D.
Assistant Examiner: Staab; Lawrence J.
Attorney, Agent or Firm: Keating; William J. Raring;
Frederick W. Seitchik; Jay L.
Claims
What is claimed is:
1. An electrical connector comprising an elongate spring body
having a generally uniform cross-section, which is resiliently
deformable transversely of its length and which has discrete
conductive paths disposed in insulating spaced relationship around
the body, said conductive paths comprising a conductor wire coil
wound around said spring body and being disposed in closely
uniformly spaced turns along said body, said conductor wire being
bonded to said body and having a portion removed from each said
turn thereby forming said discrete conductive paths, each path
being of generally C-shaped turn form extending around part only of
the circumferential periphery of the spring body, each path further
comprising a lead portion extending freely away from said spring
body, said lead portion being an integral part of the coil wound
conductor wire, and exposed surface portions of the wire on each
said turn defining at least a row of contact points distal from and
extending along the spring body.
2. A connector as claimed in claim 1, in which the C-shaped turns
extend around more than half of the circumferential periphery of
the body and present diametrically opposite rows of contact points
extending longitudinally of the spring body.
3. A connector as claimed in claim 2, in which the spring body is
formed of elastomeric insulating material.
4. A connector as claimed in claim 2, in which the spring body is a
tubular form of C-shaped cross-section.
5. A connector as claimed in claim 4 in which the tubular spring
body is of metal and the wire turns are electrically insulated from
the spring body.
6. A connector as claimed in claim 5 in which the wire turns are of
insulated wire from which the insulation is removed at exposed
surface portions distal from the spring body to define at least one
row of contact points extending longitudinally of the spring
body.
7. A connector as claimed in claim 2 in which the contact points
are defined by spot depositions of metal plating on the exposed
wire surface portions.
Description
This invention relates to electrical connectors and their method of
manufacture. It is particularly but not exclusively concerned with
connectors for connecting to or interconnecting lamina circuits
such as are formed on printed circuit boards or substrates.
There is increasing need to effect releasable connection to circuit
boards or substrates containing large numbers of integrated
circuits and presenting large numbers of closely spaced connection
points. It is important that such boards or substrates can readily
be released from their interconnection within a greater circuit
package for maintenance purposes. Conventional connectors have
largely proved unsatisfactory in adaptation to the small sizes of
connector and small contact pitch required.
It is an object of the present invention to provide a connector of
a kind suitable for manufacture in small sizes with small contact
pitch and to provide an economic manner of manufacture for such a
connector.
An electrical connector according to the present invention
comprises an elongate spring body having a generally uniform
cross-section, which is resiliently deformable transversely of its
length and which has discrete conductive paths disposed in
insulating spaced relationship around the body in which each path
comprises a conductor wire of generally C-shaped turn form
extending around part only of the circumferential periphery of and
bonded to the body, exposed surface portions of the wire turns
defining at least a row of contact points distal from and extending
along the spring body.
In one embodiment the wire of each C-shaped turn of at least one of
the ends of the C-shape extends freely away from the spring body as
a lead.
Suitably, the C-shaped turns extend around more than half of the
circumferential periphery of the body and present diametrically
opposite rows of contact points extending longitudinally of the
body.
The spring body may be formed of elastomeric insulating material or
for example it may be formed as a tubular spring of C-shaped
cross-section. Such a spring may be of metal in which case the
spring turns are insulated from the metal.
In a method of manufacture of an electrical connector according to
the present invention, a single layer coil of conductor wire is
wound around the spring body to extend longitudinally in closely
spaced turns, the turns being bonded to the body and the coil being
cut longitudinally of the body to separate adjacent turns which
define the discrete conductive paths.
In a particular form of this method, the spring body is initially
located beside a former body extending longitudinally of and
projecting laterally from the spring body, the coil being wound in
turns about the two bodies and cut longitudinally of the coil at
turn portions around the former body, the former body being removed
and wire portions extending from one or both ends of each of the
separated turns. Suitably, a pair of connectors may be made
simultaneously by disposing a former body between a pair of spring
bodies, and winding the coil about the three bodies. The turns are
then cut longitudinally of the former at locations between the
spring bodies.
In order to reduce the offset effect due to the helical nature of
coil turns, the spring body is suitably elastically deformed prior
to winding the coil in the same sense as the lead of the coil, and
is held in that condition until after the coil cutting operation
when the deformation is relaxed. The coil turns are thus
flattened.
The invention will now be described by way of example with
reference to the accompanying partly diagrammatic drawings, in
which:
FIG. 1 is a perspective view of a connector;
FIG. 2 is an end view of the connector of FIG. 1;
FIG. 3 is a fragmentary perspective view of a printed circuit board
assembly including a connector according to FIGS. 1 and 2;
FIG. 4 is an enlarged fragmentary longitudinal section of part of
the connector of FIGS. 1 and 2;
FIG. 5 is a fragmentary perspective view of a stage in the
manufacture of a connector according to FIGS. 1 and 2;
FIG. 6 is a sectional view of a printed circuit edge connector
embodying connectors according to FIGS. 1 and 2;
FIG. 7 is a fragmentary perspective view partially sectioned of a
connector block assembly embodying the invention; and
FIG. 8 is an elevation of a spring body in relaxed and deformed
conditions established during manufacture of a connector according
to the invention.
The connector of FIG. 1 comprises a tubular spring member 1 having
a generally C-shaped cross-section with a longitudinally extending
open seam 2 which may be closed by resilient deformation of the
spring. The tubular spring is of metal but alternatively it could
be of resilient insulating material or a body of elastomeric
insulating material could be substituted for the tubular spring. A
series of parallel wires 3 extend generally tangentially from the
spring 1 and the wires terminate with arcuate portions 4 extending
around and bonded to the tubular spring 1 in insulating spaced
relationship. The wires are suitably insulated with a varnish type
insulation and diametrically opposite parts of the arcuate portions
4 are cleaned of insulation on sides distal from the spring 1. The
bare metal exposed is spot plated with contact metal such as gold
or tin at 7 to provide rows 5 of contact points 6. The adhesive
bonding material as seen in FIG. 4 secures the arcuate portions in
insulating spaced relationship and allows flexure of the arcuate
portions 4 concomitant with flexure of the tubular spring 1.
In use, as seen in FIG. 3, the connector of FIGS. 1 and 2 is
clamped between opposed faces of adjacent circuit boards 9 with the
tubular spring 1 compressively flexed between the boards. Groups of
contact points 6 engage respective contacts of the circuit boards
to effect desired interconnections between the upper and lower
boards and to input or output circuits through the lead wires
3.
In order to manufacture a connector of this kind, as seen in FIG.
5, tubular springs 1 are suitably sprung onto opposite ends of a
former 10 adapted to open the spring seams 2. The former is
provided with longitudinal grooves 11 at opposite sides for wire
cutting purposes as will be described. The external arcuate
surfaces of the springs are coated with adhesive 8, FIG. 4, and a
single layer coil of wire wound around the former in a series of
closely spaced turns. After setting of the bonding adhesive,
desired contact points 6, FIG. 4 are cleaned by a skimming or
grinding process and the exposed wire portions spot plated with a
suitable contact metal 8, such as gold or tin. The wire coil is cut
along the grooves 11 to separate the two connectors which are then
removed from the former 10.
The wire ends 3 extend from both sides of the open seam 2 of each
connector, and due to the expansion of these seams during the
manufacture, the arcuate portions 4 of the wires extend around more
than a semi-circle when the spring is relaxed. The contact rows are
suitably diametrically opposite in this condition. The wire ends 3
may be selectively removed or grouped into bundles according to the
particular circuit connections required.
In the edge connector of FIG. 6 a pair of connectors according to
FIGS. 1 and 2 is positioned one on each side of a slot 12 in a
housing 13. The springs 1 are arranged with arcuate portions
projecting into the slot 12 with the rows of contact points 6
disposed to engage opposite sides of a printed circuit board 14.
The wire ends 3 lead out from the housing for circuitry connection
purposes.
It will be appreciated that the manufacture of the connector by
coil winding techniques will normally result in diametrically
opposite contact points 6 of a conductor portion 4 being helically
offset by half of a pitch. Where fine wires are used on a close
pitch and it is intended that a complementary contact surface of a
printed circuit board will engage a plurality of contact points as
a group, the half pitch offset is not material.
However, in situations where it is intended that the complementary
printed circuit or substrate circuit will engage but a single
contact point 6 then precautions must be taken to ensure selection
of the appropriate contact points on diametrically opposite
portions of the connector. In such situations it may be desirable
to wind the arcuate portions 4 as flat turns or after winding the
coil to displace marginal portions of the C-shaped spring bordering
the open seam laterally in opposite directions in order to flatten
the coil turns. This may suitably be effected by initially
stressing the spring laterally in the sense of coil winding, in
order elastically to deform the spring by an amount corresponding
to the coil pitch and after winding the coil and bonding the turns,
allowing the spring to relax from the stress to flatten the
turns.
In an embodiment of the invention as shown in FIG. 7 the connector
spring body is contained in an insulating housing 15 comprising
identical halves 16, 17 snap-fitting together and about the spring
body 1. Each housing half 16, 17 contain means, not shown, to
engage ends of the spring body 1 at each side of the seam and
arranged on closure of the two housing halves 16, 17 together to
displace marginal portions of the spring body on each side of the
seam relatively laterally in order to flatten the coil turns 4.
Each housing half 16, 17 has a groove-like recess 18, 19 receiving
the spring body 1, and a plurality of passageways 20, 21 extending
transversely of the recess and intersecting the recess generally
tangentially of the spring body. Conductor wires 22 may be threaded
into the passageways and clamped in position by resilient pressure
of the spring body 1 which provides mechanical retention and
contact pressure. Such an arrangement is applicable to flat
flexible or tape cables, in which case a slot is provided for
reception of the multiconductor cable in place of a plurality of
passageways 22.
In FIG. 8 a spring body 1 of C-shaped section showing in broken
lines 1' how it may be elastically deformed by lateral displacement
on opposite sides of the seam prior to coil winding so that on
relaxation afterwards, the helical coil turns are flattened. It
will be appreciated that the broken line position represents a
single turn helix of the same pitch and lead sense as the coil
winding.
* * * * *