U.S. patent number 3,594,712 [Application Number 04/774,027] was granted by the patent office on 1971-07-20 for connector.
This patent grant is currently assigned to Minnesota Mining and Manufacturing Company. Invention is credited to Dennis J. Enright, Leonard H. Schrenkler.
United States Patent |
3,594,712 |
Enright , et al. |
July 20, 1971 |
CONNECTOR
Abstract
A solderless wire-connector comprises a slotted thin resilient
metal plate supported against a correspondingly slotted rigid base
having a wire cutoff anvil surface.
Inventors: |
Enright; Dennis J. (St. Paul,
MN), Schrenkler; Leonard H. (St. Paul, MN) |
Assignee: |
Minnesota Mining and Manufacturing
Company (St. Paul, MN)
|
Family
ID: |
25100026 |
Appl.
No.: |
04/774,027 |
Filed: |
November 7, 1968 |
Current U.S.
Class: |
439/709;
439/723 |
Current CPC
Class: |
H01R
4/2429 (20130101); H01R 43/015 (20130101) |
Current International
Class: |
H01R
4/24 (20060101); H01R 43/01 (20060101); H01r
009/08 (); H01r 009/17 () |
Field of
Search: |
;339/95,221,96,97,98,99,198,242 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Moore; Richard E.
Claims
What we claim is as follows:
1. A solderless connector for supporting and making electrical
contact with an insulated wire, comprising: a rigid block having a
short leg and a parallel extended leg defining a narrow groove
therebetween, said short leg having a flat fully exposed terminal
surface generally perpendicular to said extended leg, and said
extended leg being bifurcate and defining a narrow wire-accepting
slot; and a thin bifurcate conductive resilient contact plate
fitting tightly within said groove and substantially against said
extended leg and defining a deep narrow slot in line with said slot
in said leg, for receiving and making resilient permanent spring
compression reserve contact with a wire forcefully inserted into
said slots and against said terminal surface.
2. Connector of claim 1 wherein said block is of rigid electrical
insulation material.
3. Connector of claim 2 wherein said contact plate is extended from
the bifurcate wire-contacting portion to form at least one
additional contact member.
4. Connector of claim 3 wherein a said additional contact member is
in the form of a contact post.
5. Connector of claim 3 wherein a said additional contact member
includes at least one additional bifurcate wire-contacting
portion.
6. Connector of claim 3 wherein a said additional contact member is
in the form of a flat plate spring contact.
7. Connector of claim 3 wherein a said additional contact member is
in the form of at least one resilient tubular contact member.
8. Connector of claim 3 wherein one said additional contact member
is a second thin bifurcate contact plate and another said
additional contact member is in the form of a flat plate spring
contact.
9. A telephone connecting block including a flat base for
attachment to a supporting structure, and integral therewith, a
plurality of solderless connectors as defined in claim 6.
Description
This invention relates to electrical connectors, and in particular
to solderless connectors for insulated small wires.
In one important aspect of the invention there is provided a
solderless wire-connector useful as a component of telephone
terminal connectors for making connection between two or more
insulated wires or with another wire carrying a fork or plug-type
terminal. A number of connector elements may be incorporated in a
single terminal for making connection with other wires within the
circuitry or with leads from external instruments or appliances. An
example is a telephone connecting block wherein is provided five
spade or fork sockets each with one or more solderless
wire-connectors forming a part thereof, for facilitating the
installation of telephone outlets.
The invention employs thin resilient slotted plate contact members
similar in many respects to those described for example in U.S.
Pat. Nos. 3,012,219 and 3,202,957 but possessing a number of
additional advantages. The connector typically need consist only of
a supporting base and a contact element. The connection, once
formed, remains in full view. The contact member may be easily
extended and formed into contact elements of other desired
configuration.
The connectors of the present invention additionally provide means
for the ready removal of excess wire in forming a terminal
connection, as well as providing desirable strain relief in the
completed connection.
In the drawing,
FIG. 1 is a view in perspective of a wire-connector designed to
make connection between a wire-end and a contact post;
FIG. 2 illustrates in perspective, with portions cut away to show
interior structure, a wire-connector for making contact between a
wire-end and a fork-type terminal;
FIG. 2a, is a partial sectional view taken approximately at section
a--a of FIG. 2;
FIG. 3 is a view in perspective of a wire-connector for connecting
together two wire-ends and including in phantom an optional
extension similar to that of FIG. 2;
FIG. 4 is a view in perspective of a connector with an inserted
wire-end and suitable for making contact with plug-type
terminals;
FIG. 5 is a partial view taken approximately at section 5-5 of FIG.
4, showing the application of a wire-end to a wire-connector by
means of an applicator and cutoff tool; and
FIG. 6 is a plan view showing the assembly of five wire-connector
and fork socket terminals in a telephone connecting block.
In each instance the solderless wire-connector will be seen to
comprise a thin resilient contact plate and a rigid block or backup
member. The contact plate is bifurcate, being deeply narrowly
slotted from one edge to form a wire-accepting open-mouthed slot.
The block has a short leg and a parallel extended leg, the two
defining a narrow transverse groove therebetween, the contact plate
fitting tightly therein. The extended leg is bifurcate and defines
a longitudinal slot in line with the slot of the contact plate, and
has a flat surface with which the contact plate is in close
proximity or actual contact. The shorter leg of the block has a
flat terminal surface which is generally perpendicular to both the
extended leg and the slot therein and serves as a platform or anvil
for subsequent cutting of the wire-end thereagainst if desired. The
contact plate is retained within the groove in the base, and may be
extended in any desired direction to provide for connection with
additional contact members as desired.
In FIG. 1 is shown wire-connector 10 having a contact plate 11
extended to form a contact post 12 and supported within a laterally
grooved block 13 which is additionally centrally perforated to
permit passage of the post 12. The plate 11 is deeply slotted from
the outer end to form two opposing legs defining an open-mouthed
wire-accepting slot 14, and is disposed in snug face-to-face
contact with the flat inner face of the bifurcate leg 15, the
narrow slot of the plate 11 and the somewhat wider slot of the leg
15 being in alignment. The short leg of the block 13 terminates in
a flat platform surface 16 at or slightly above the base of the
slot 14 in the plate 11 and perpendicular to the contact element 11
and the leg 15.
Closely similar structure is shown at the left-hand portion of the
connector 20 as illustrated in FIGS. 2 and 2a. In this modification
the block 23 is extended laterally to provide an enclosure for a
lateral extension 27 of the contact plate 21, and is laterally
grooved to form a groove 29 of extended width for entry of a fork
terminal 28. The extension 27 is at an acute angle with the plane
of the plate 21 and the inner surface of the block to provide for
easy insertion of a terminal 28 as indicated, and is protected and
held in place by an inner ledge 7 which may be formed by upsetting
the edge of the block 23 as shown in FIG. 2a. The bottom of the
groove 29 is centrally extended in an inverted V-shaped portion 8
for centering the inserted fork terminal 28.
In the connector 30 of FIG. 3, a double contact plate element 31 is
supported within a double block member 33 to provide for connecting
together two wire-ends, thereby providing two bifurcate contact
elements having one leg in common. It will be appreciated that the
two bifurcate contact elements may alternatively be independent but
interconnected.
The connector 40 of FIGS. 4 and 5 comprises a laterally extended
bifurcate deeply slotted contact plate 41 retained within a
transversely grooved block 43 having a correspondingly slotted and
laterally extended longer leg 45 and a shorter leg having a cutoff
face 46. In this modification the extended portion of the plate 41
is formed into two parallel resilient tubelike receptacles 47 for
plug-type terminals. FIGS. 4 and 5 additionally show an insulated
wire-end 48 disposed within the slotted contact plate and making
electrical connection therewith. A line 49 represents the slight
depression left by the cutoff tool in applying and severing the
wire.
The introduction of the wire-end into the connector, and the
removal of unnecessary portions of said wire-end, are shown in more
detail in FIG. 5. The plate 41 is seated in the transverse groove
42 of the base 43. The end of the slot in the plate 41 is slightly
below the upper level of the terminal surface 46 of the shorter leg
of the block 43. The wire-end 48 is forced into the narrow slot in
the plate 41 by means of the wedge-shaped blade 57 of a
hollow-ended special tool 55 available from telephone installation
supply sources. Alternatively, the wire may be forced into the
slotted plate using an ordinary screwdriver and if desired may then
be cut against the anvil surface by means of a knife or chisel.
The force required to insert the wire-end into the slotted plate
against the resiliency of the spring brass or other metal of which
the plate is constructed would normally have a tendency to cause
undue deformation or buckling of the unsupported plate element. In
the device of the present invention, however, the plate is
supported and reinforced at the one face by the leg 45 of the rigid
block and from the opposing face by the presence of the tool 55, so
that the contact element is prevented from buckling or folding and
is therefore retained in planar configuration and capable of
providing permanent resilient or spring compression reserve contact
between the slot-defining edges of the plate and the metallic
conductor of the wire 48, as illustrated by the contact area 44.
The sharpened extended blade 57 of the tool 55 pressing toward the
flat surface 46 acts effectively to shear the wire at a plane
slightly removed from the plate 41, so that the excess end portion
50 may be removed and so that there is no subsequent possibility of
tension being applied to the wire in a direction tending to remove
the plate from face-to-face contact with the leg 45. Any tension
applied to the wire 48 serves only to force the plate 41 more
firmly against the leg 45, which thus provides strain relief to the
connection.
In a specific example and as illustrated in FIG. 2, a solderless
connector made in accordance with the principles of the invention
and to a size suitable for handling telephone switchboard or
connector block connections employs a bifurcate or U-shaped contact
element 21 made from 24 to 28 gage cartridge brass plate and having
a width of 0.16 inch, the remaining dimensions being proportionate.
The bifurcate longer leg of the block 23 is 0.125 inch in thickness
and has a total length of 0.30 inch; the shorter leg has a total
length of 0.11 inch. The block is ordinarily formed of hard
thermoplastic polymer, such as medium or high impact
acrylonitrile-butadiene-styrene terpolymer, by injection molding
procedures but may alternatively be made in other ways and of other
thermoplastic or thermosetting materials having good insulating and
heat-resistance properties, such for example as a phenolic resin or
a polycarbonate plastic, or even of metal when only structural
rather than electrical connections are involved.
FIG. 6 illustrates an application wherein a number of the
connectors 20 of FIG. 2 are combined in a single terminal box or
block, in this instance a telephone connecting block 60. The base
61 of the block, molded in a single piece with the blocks of the
connectors, has a narrow recessed margin 62 to receive a cover, not
shown. Wire or cable entry ports 63,64 are provided at opposite
sides and a central guide and strain relief post 65 provides means
for positioning and holding the wires. Loose wire-ends from a
telephone dropline are attached to the slotted contact plates, and
excess lengths of wire are removed, by the procedures described in
connection with FIGS. 4 and 5. Fork terminals attached to the
telephone cord are inserted into the grooves 29 and against the
resilient contact plate extensions 27 of the connectors 20 as
described in connection with FIGS. 2 and 2a. Twin wire-contacts as
described in connection with FIG. 3 may be used in place of the
single contact of FIG. 2 where additional connections are desired,
as shown in phantom in FIG. 3 by block extension 23' and flat plate
extension 27' of contact element 31; and other combinations and
modifications may be provided. The base 61 is provided on its flat
outer surface with a resiliently compressible pressure-sensitive
adhesive bonding layer for convenience in applying to desk, wall,
or other surfaces.
* * * * *