U.S. patent number 3,805,214 [Application Number 05/282,823] was granted by the patent office on 1974-04-16 for resilient electrical contact.
This patent grant is currently assigned to AMP Incorporated. Invention is credited to Henry William Demler, Sr., Paul Joseph Minchhoff.
United States Patent |
3,805,214 |
Demler, Sr. , et
al. |
April 16, 1974 |
**Please see images for:
( Certificate of Correction ) ** |
RESILIENT ELECTRICAL CONTACT
Abstract
An electrical contact for an electrical wire having a first
slotted member for receiving the wire and a pair of supporting
members integrally formed with, and disposed upon opposite sides of
the slotted member for providing a strain-relief function for the
wire, the configuration of the contact being S-shaped in
cross-section. A hand tool is provided for inserting the wire
within the contact, the tool having pivotable and fixed hand-grip
members for actuating a spring biased reciprocable ram and anvil
assembly. Operation of the hand-grip members actuates the ram-anvil
assembly which inserts the wire within the contact while
simultaneously releasing the tool from the contact.
Inventors: |
Demler, Sr.; Henry William
(Lebanon, PA), Minchhoff; Paul Joseph (Harrisburg, PA) |
Assignee: |
AMP Incorporated (Harrisburg,
PA)
|
Family
ID: |
23083280 |
Appl.
No.: |
05/282,823 |
Filed: |
August 22, 1972 |
Current U.S.
Class: |
439/83;
439/399 |
Current CPC
Class: |
H01R
4/245 (20130101); H01R 43/015 (20130101) |
Current International
Class: |
H01R
43/01 (20060101); H01R 4/24 (20060101); H01r
011/20 (); H05k 001/02 () |
Field of
Search: |
;339/95-99,103,107,276T,256-258,17R,17C,275 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
1,640,633 |
|
Oct 1969 |
|
DT |
|
1,963,313 |
|
Jun 1971 |
|
DT |
|
Primary Examiner: Gay; Bobby R.
Assistant Examiner: Lewis; Terrell P.
Attorney, Agent or Firm: Kita, Esq.; Gerald K.
Claims
What is claimed as new and desired to be secured by Letters Patent
of the
1. In the combination of the printed circuit board and an
electrically conducting contact mounted thereto, the combination
comprising:
an elongated portion of said contact mounted fixedly in said
printed circuit board,
a generally S-shaped portion of said contact integral with said
elongated portion and mounted adjacent one surface of said printed
circuit board,
a pair of outer contact portions of said S-shaped portion being
bifurcated with slots for wedgingly receiving an insulated wire
therein,
a central projecting contact portion of said S-shaped portion
having a slot therein adapted for wedgingly receiving an insulated
wire therein,
the slot of said central contact portion being adapted to slice
through the insulation of an insulation covered wire wedgingly
received in said slot to establish electrical connection between
the insulation covered wire and the edges of said central contact
portion along the slot thereof,
the two outer contact portions of said S-shaped portion projecting
above the central portion, and
an enlarged wire receiving opening in each outer contact portion,
each of said openings being located outwardly above the central
contact portion of
2. The structure as recited in claim 1, wherein, said outer contact
portions of said S-shaped portion are provided with points on
either side
3. An electrical terminal adapted for insertion in a printed
circuit board, comprising:
a central elongated arm portion adapted for insertion in a printed
circuit board,
a first contact portion integral with said arm portion and
projecting above said arm portion,
said first contact portion having a slot therein communicating with
one side of said contact portion,
the sides of said first contact portion adjacent said slot defining
resilient cantilever beams, whereby an insulation covered wire may
be forcibly inserted into said slot from one side of said first
contact portion and retained in compression between said cantilever
beams with the beams slicing through the insulation for electrical
contact with the wire,
a pair of additional contact portions integral with said first
contact portion, said first contact protion being disposed between
said additional contact portions,
each said additional contact portion having a slot therein
extending from one side thereof, whereby an insulation covered wire
may be anchored and supported by its insulation within the slot of
each said additional contact portion to resist pull-out of the wire
from the first contact portion, and
the slot of said first contact portion being in alignment with the
slot of each said additional contact portion, whereby a
substantially straight length of an insulation convered wire may be
extended through each of said
4. The structure as recited in claim 3, wherein,
each said additional contact portion having an enlarged entrance
portion opening into said slot,
each said additional contact portion projecting above said first
contact portion, whereby an insulation covered wire may be received
into said enlarged entrance portions projecting above said first
contact portion.
5. In the combination of a printed circuit board and a contact as
recited in claim 1, the improvement comprising:
each said outer contact portion having a depending projecting tab
in engagement on said printed circuit board for location of said
contact
6. An electrical contact, the combination comprising:
a pair of wire-receiving strain relief members on said contact,
a wire receiving contact element disposed between said strain
relief members,
each said strain relief members having a slot therein, the slots of
said strain relief members being in alignment with each other,
said wire receiving contact element having a slot therein in
alignment with each slot of said strain relief members,
the slot of said wire receiving contact element being of lesser
width than either slot of said strain relief members, whereby a
relatively straight length of insulation covered wire may be
wedgingly received in the aligned slots, with the wire receiving
contact element adapted for slicing through the insulation for
electrical contact with the wire, and with the strain relief
members anchoring the insulation covered wire on either side of
said wire receiving contact element;
said wire receiving contact element being integral with each said
strain relief member, and
an elongated portion integral with said wire receiving contact
element and
7. The structure as recited in claim 6, wherein, each said wire
receiving strain relief members includes a projecting portion which
projects above said wire receiving contact member, and
an enlarged entrance opening portion provided in each projecting
portion of a corresponding strain relief member,
each said enlarged entrance opening portion communicating with said
slot of
8. The structure as recited in claim 7, wherein, said projecting
portion of each strain relief member is pointed on either side of a
corresponding enlarged entrance opening portion.
Description
BACKGROUND OF THE INVENTION
This invention relates generally to electrical connectors, and mroe
particularly to an "S"-shaped electrical wire contact having high
structural integrity and a tool for inserting the wire into the
contact.
It is often desirable to make electrical contact with an insulated
wire without the necessity of using solder or multi-step mechanical
aids. In order to satisfy such requirement, prior art devices have
been utilized with varying degrees of success which include a "U"
or "V"-shaped grooved conductive member for cutting through the
insulation and resiliently holding and completing a conductive path
with the wire. Although such prior art devices have been generally
successful, the structural integrity of such devices has not been
wholly satisfactory and in fact usually requires the contacts to be
mounted in a housing for support. A further problem with such
devices resides in that they are generally susceptible to a high
level of strain in the wire at the contact point resulting in some
occurrances of wire dislodgement or breakage.
SUMMARY OF THE INVENTION
Accordingly, one object of this invention is to provide a new and
improved electrical contact having good structural integrity.
Another object of the invention is the provision of a novel
electrical contact having good structural integrity without the
requirement of a housing.
Still another object of the present invention is to provide a new
and improved electrical contact which provides strain relief for a
wire inserted therein.
A still further object of the present invention is the provision of
a new and improved electrical contact which is relatively small and
economical to manufacture.
A still further object of the present invention is the provision of
a new and improved electrical contact which is readily adaptable
for point-to-point wiring, with a plurality of contacts being
mounted in a printed circuit board (P.C. board).
Another object of the present invention is to provide a tool for
electrically connecting individual wires or wires of a ribbon cable
from point-to-point locations defined by a plurality of contacts
according to the present invention mounted in a P.C. board, the
tool being capable of cutting wires at selected contacts or
alternatively inserting wires into the contacts without
cutting.
One further object of the present invention is the provision of a
novel electrical contact having high structural integrity and a
novel tool for electrically connecting a wire in such contact and
for selectively cutting off said wire at such contact.
Briefly, in accordance with one embodiment of this invention, these
and other objects are obtained by providing an electrical contact
capable of receiving a wire therein, the contact including a
resilient contact having a slot defined therein for receiving and
making electrical contact with the wire, and a pair of oppositely
disposed strain relief elements integrally formed with the
contact.
BRIEF DESCRIPTION OF THE DRAWING
A more complete appreciation of the invention and many of the
attendant advantages thereof will be readily appreciated as the
same becomes better understood by reference to the following
detailed description when considered in connection with the
accompanying drawing, wherein:
FIG. 1 is a plan view of the connector of the present invention
attached to a carrier strip at one stage of manufacture
thereof;
FIG. 2 is a perspective view of the electrical contact of the
present invention;
FIG. 3 is a top view of the contact of the present invention as
viewed in the direction of the arrow 3 shown in FIG. 2;
FIG. 4 is a partial sectional view taken along the line 4--4 of
FIG. 3 showing one insulation contact;
FIG. 5 is a partial sectional view taken along the line 5--5 of
FIG. 2, with parts not shown, of the wire contact of the present
invention;
FIG. 6 is a side view of the tool of the present invention with
parts in section;
FIG. 7 is an exploded view of the operative portions of the tool of
FIG. 6;
FIG. 8 is a sectional view of the operative portions of the tool of
FIG. 6 in a first position illustrating the assembly of a wire to a
contact;
FIG. 9 is a sectional view of the operative portions of the tool of
FIG. 6 in a second position of the assembly of a wire in a contact;
and,
FIG. 10 is a sectional view of the operative portions of the tool
of FIG. 6 illustrating the combination of assembling a wire with
the contact and cutting off the wire at the contact.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings, wherein like reference characters
designate identical or corresponding parts throughout the several
views, and more particularly to FIG. 1 wherein an electrical
contact of the present invention is illustrated generally at 12
attached to a carrier strip 14. The contact 12 as illustrated in
FIG. 1 has undergone a first step of manufacture wherein the
contact and associated carrier strip have been punched or
chemically etched from a flat strip or sheet of conductive
material, and wherein a knife edge portion 16 has been formed by
providing a break line 18 between the contact 12 and the carrier
strip 14.
A center contact arm 20 is provided at the base of the contact for
extension through a PC board to the like and may consist of any
known contact shape. A first bifurcated portion 22 provides a wire
contact which is in longitudinal alignment with the center contact
arm 20 and a pair of symmetrically designed insulation contacts
indicated generally at 24 and 26 are provided at opposed sides of
the wire contact 22. In order to form the contact into the shape as
actually used, the insulation contacts 24 and 26 are respectively
bent in opposed directions so as to be in alignment with wire
contact 22, as shown in FIGS. 2 and 3.
The contact 12 when in the fully formed condition, as shown in
FIGS. 2 and 3, is capable of providing good structural integrity
due to the generally S-shaped construction, and can be used with
non-insulated wire, insulated wire, ribbon type cable and the like.
The bifurcated wire contact 22 is provided with a contact wedge
slot 28 having a width of such dimension that the wire contact will
cut through any insulation about the wire and will compress
opposite sides of the wire as the insulated wire is forcibly
inserted into the wedge slot. The wire is compressed to an oval
shape and the opposite sides thereof are wiped upon forcible
insertion in the slot, to provide wiping of the wire surfaces and
the slot surfaces for good electrical conductivity, as shown most
particularly in FIG. 5. Also the outer sides 30 of the contact act
as opposed resilient cantilever beams which, upon forcible
insertion of the wire between the beams, provide resilient
cantilever compression on the inserted wire to assure forcible
contact with the wire for good conductivity. The outer sides 30 of
the wire contact are substantially straight so as to provide
strength to the wire contact while the contact retains a generally
resilient nature. The knife edge 16 provided on each of the
bifurcated portions of the wire contact enable the contact to cut
through the insulation on ribbon type cable when the contact is
used in conjunction therewith. The knife edge 16 is outwardly
angled as at 32 so as to provide a notch capable of easily
receiving an insulated wire and for funneling the wire into the
slot 28.
Insulation contacts 24 and 26 are each bifurcated and provided with
central grooves or slots 34 and 36, respectively, which are in
alignment with contact wedge slot 28 such that a wire received in
the center slot would be likewise received in the grooves or slots
34 and 36 with the wire in a straight position such that strain
relief and resistance to pull-out would be provided therefor. The
width of slots 34 and 36 is dimensioned such that a wire placed
along the slots would be supported by its insulation to adequately
provide strain relief and resist pull-out of the wire from the
contact 22 as shown in FIG. 4. Each of the bifurcated portions of
the insulation support contacts is provided with an entrance angle
portion 38 and an outside angle portion 40 meeting at a point 42
such that when used with wires in side-by-side relationship in an
insulation covering in a ribbon type cable 43 or the like, instead
of individual insulation covered wires, the piercing points 42
easily cut through the insulating portions 45 of the ribbon type
cable and the entrance angles funnel the conductor into the
insulating support grooves 34 and 36. As shown in FIG. 2, the
piercing points 42 are on both sides of and extend above the
central contact slot 32. As the ribbon type cable is forced into
contact with the terminal 26, the points 42 will initially engage
and then cut through the insulating portions 45, thereby dividing
out a single wire from the insulating portions 45. The single wire
is then free from the insulation portions 45 for forcible insertion
into the contact slot 32. Locating tabs 44 and 46 are integrally
formed and downwardly extended at each insulation contact 24 and
26, respectively, and are provided with a flat base portion for
engagement with a PC board or the like. As shown in FIG. 4, the
individual wire 47 in the grooves 34 and 36 is in compression but
in less compression than in the slot 28.
It can be seen that the unique construction of the contact of the
present invention provides good structural integrity due to the
generally "S"-shape, and provides strain relief for a wire held by
and anchored in the insulation contacts 34 and 36 while the wire is
in good electrical contact with the contact wedge slot 28. Since
good structural integrity is provided in the construction of the
contact of the present invention, and since the wire is effectively
anchored to the contact support grooves 34 and 36 on either side of
the contact slot 28, resistance to pull-out of the wire from either
side of the contact slot 28 is assured, and there is no necessity
for providing a separate housing or support for the contact, as has
been generally necessitated by the prior art devices.
It is noted that with reference to FIGS. 8 through 10, that the
triple wedge contacts of the present invention are typically
inserted within through holes in a PC board with their locating
tabs 44 and 46 in appropriate position such that the tabs abut the
PC board thereby positioning the contacts at a predetermined height
above the board.
In order to properly position the wire within the miniaturized
contact of the present invention, it is hightly advantageous to
utilize the particular hand tool having the unique and novel
configuration disclosed in FIGS. 6 through 10. The unique tool
disclosed therein comprises a housing 48 which has a handle 50
integral therewith and a hand grip 52 which is pivotally mounted
with respect to the housing 48 and handle 50 by means of pivot pin
54. An actuating extension 56 is integrally fixed upon hand grip
52, one surface of extension 56 being adjustably abutted by a set
screw 58 which determines the extent of travel of extension 56 and
hand grip 52 in one direction. Defined within housing 48 is a first
cylindrical bore 60 and a second reduced cylindrical bore 62 for
receiving a cylindrical ram 64 therein. The rear terminal portion
of ram 64 comprises a flanged section 66 which abuts another
surface of actuating extension 56. Surrounding cylindrical ram 64
and seated within the larger bore 60 is a coil compression spring
68, the ends of spring 68 abutting flange portion 66 and the
reduced diameter portion of bore 60 and 62, spring 68 thereby
maintaining ram 64 in its retracted mode upon the release of hand
grip 52 as shown in FIG. 6.
The forward operative portion of the tool includes a pusher member
70, a contact holder 72, and a wire cutter 74. Contact holder 72 is
fixed relative to housing 48 via an internally threaded sleeve 76.
Referring more particularly to FIGS. 7 and 8, it is seen that the
forward portion of contact holder 72 comprises a pair of resilient
holding fingers 78. Contact holder 72 additionally comprises a
first bore 80 having a diameter sufficient for retaining the larger
diameter of the ram 64. Ram 64 further comprises a flattened area
82 for cooperation with a retaining pin 84 situated within the bore
80, pin 84 thereby preventing any rotation of ram 64 relative to
bore 80. Contact holder 72 additionally comprises second, third and
fourth cylindrical bores 86, 88 and 90, of consecutively diminished
diameters, the third cylindrical bore 88 further containing a
generally ovoid aperture 92 for providing flexures 94 which in turn
resiliently bias holding fingers 78. Holding fingers 78 define
therebetween a wire receiving slot 96. A retaining pin 98 laterally
disposed within the forward portion of ram 64 secures a pusher
element 100 within an aperture formed within such forward portion,
pusher element 100 further containing an anvil member 110.
Referring now to FIG. 8, a wire 112 is disclosed as being
positioned within wire receiving slot 96 in abutting relationship
with the forward portion of anvil 110 which is in its fully
retracted mode. When pressure is exerted upon an end section of
housing 48 in a longitudinal direction relative to the housing,
holding fingers 78 will come into contact with the outside angle
portions 40 of electrical contact 12 via camming surfaces 114.
Continued application of pressure, causes camming surfaces 114 to
slide upon angle portions 40 in a generally longitudinal direction,
such action simultaneously spreading apart fingers 78, fingers 78
further sliding upon exterior portions 41 of contact 12 which are
parallel to the longitudinal axis of contact 12, the sliding action
in the spread mode continuing until the fingers 78 reach the lower
terminal portion 43 of contact 12, whereupon fingers 78 will
radially contract so as to lock themselves with contact 12, thereby
preventing removal of the tool relative to the contact. It is noted
that the locating tabs 44 and 46 are appropriately positioned
relative to the tool such that the fingers 78 are enabled to lock
with the contact 12 and in addition, the anvil 110, wire 112, and
the grooves 28, 34, and 36, are all in proper alignment.
Referring again to FIG. 6, as the hand grip 52 is squeezed relative
to handle 50, extension member 56 pivots around pivot pin 54
thereby abutting flange portion 66 of ram 64 so as to
longitudinally move ram 64 against the action of coil spring 68.
Movement of ram 64 in turn causes longitudinal movement of anvil
member 110, thus advancing wire 112 from its position disclosed in
FIG. 8 to that disclosed in FIG. 9. Simultaneously with the
aforementioned action, a pair of ram cam surfaces 116 abuts the
upper portion of slot 96 so as to laterally spread the resilient
fingers 78, thus releasing the tool from the contact 12.
Wire cutter 74 consists of a tubular sleeve having a first bore
portion 118 for surroundingly engaging an outer wall protion 120 of
contact holder 72, the sleeve being additionally provided with a
pair of slots 112 which respectively receive the pair of pins 124
which are fixed within outer wall 120 such that the wire cutter 74
may be rotated relative to contact holder 72. Extending downwardly
from the sleeve of wire cutter 74 is a pair of cutting members 126
and 128, the cutting members being identical in construction but
oppositely faced. Each of the cutting members 126 and 128 includes
a pair of cutting edges 130 and 132 such that by rotating the
member 74 either clockwise or counterclockwise, one side of the
wire can be selectively aligned with the cutting edges. As the ram
64 is moved from the operative position shown in FIG. 8 to the
operative position shown in FIGS. 9 or 10, the wire would first be
cut, as shown in FIG. 10, and would secondly be inserted within the
grooves of the contact. The tool thus is utilized to bridge between
and electrically connect a wire from point-to-point locations
defined by two or more spaced contacts 12 mounted on a PC board
without a need for severing the wire. Alternatively, the wire may
be connected to a selected contact 12 on the PC board and then
severed, thus ending the wire at its connection to the selected
contact 12.
Obviously, numerous modifications and variations of the present
invention are possible in light of the above teachings. It is
therefore to be understood that within the scope of the appended
claims, the invention may be practiced otherwise than as
specifically described herein. For example, although a specific
novel tool has been disclosed for inserting the wire within the
contact of the present invention, it is to be noted that the wire
could be inserted by hand or by other tools. Also, for example, the
slot portions 28 and 34 and 36 may be tapered in width such that a
wire being progressively forced toward the bottom of the slot
becomes progressively compressed in narrower widths of the tapered
slots.
* * * * *