Push-in wire connector

A push-in wire connector for providing electrical connection between two or more conductors includes a housing defining an enclosure with a one-piece, conductive clip disposed in the housing. There are apertures in the housing to permit entry of the wires which are to be connected. The clip has first and second portions. The first portion is held fixed in the housing and the second portion is folded back on the first to define a cantilever spring. The spring is normally disposed opposite the apertures. When conductors are inserted into the housing they deflect the spring. The spring is then engaged with the wires to impart a clamping force which retains the wires in the housing. The clip is made of a bimetallic strip of material which, when heated by electrical current, expands in such a manner that the clamping force on the wires is increased. The exterior of the housing has a dovetail pin and socket arrangement which permits stacking of multiple, like connectors.

SUMMARY OF THE INVENTION 
This invention relates to push-in electrical connectors of the type wherein 
the stripped ends of electrical wires are pushed into the connector for 
the purpose of making electrical and mechanical connection between the 
wires. 
A primary object of the invention is an electrical connector having a 
conductive clip of relatively simple design which is convenient to 
fabricate. 
A further object of the invention is an electrical connector having a pin 
and socket arrangement on its exterior surface allowing stacking of 
multiple, like connectors. 
Yet another object of the invention is an electrical connector of the type 
described having a conductive clip made of a bimetallic strip which is 
configured so as to increase the clamping force on connected wires when 
the clip is heated by electric current. 
Another object of the invention is an electrical connector which is as 
small as possible for a three-piece structure. 
Another object of the invention is an electrical connector with which 
connections can be rapidly and easily made. 
Another object of the invention is a wire connector which can accommodate 
different size wires in one unit. 
Another object of the invention is an electrical connector having a 
conductive clip with individual fingers which can operate independently to 
engage the conductors of the wires inserted into the connector. The 
fingers may have V-shaped notches formed on the ends of the fingers to 
grip the conductors inserted into the connector. 
A further object of the invention is an electrical conductor having a 
conductive clip comprising first and second portions. The first portion is 
a flat plate. The second portion is a U-shaped piece cantilevered from the 
end of the base and extending toward the plate. The U-shaped piece is 
located adjacent the openings for the wires. There are holes in the 
U-shaped piece permitting entrance of the wire conductors. 
These and other objects will appear from time to time in the following 
specification, drawings and claims.

DETAILED DESCRIPTION OF THE INVENTION 
FIGS. 1-4 illustrate the exterior portion of the electrical connector 10 of 
the present invention. The connector is used to make electrical connection 
between two or more wires 12. The wires are of the type having a conductor 
14 surrounded by insulation 16. 
The connector 10 comprises a housing, shown generally at 18. The housing 
has a body member formed by side walls 20, a top wall 22, a bottom wall 24 
and one end wall 26. Four lugs 27 are formed on the interior surface of 
end wall 26. The walls define a five-sided, hollow enclosure having an 
open side indicated at 28. The housing can by made of nylon, polypropylene 
or any suitable thermoplastic material. 
The open side 28 of the body member is substantially filled by an insert 
30, as best seen in FIGS. 3, 5 and 6. The insert has tabs 32 on its upper 
and lower surfaces. The tabs extend into openings 34 in the top and bottom 
walls of the body member to retain the insert in the enclosure of the body 
member as described below. The insert has a plurality of apertures 36 
extending therethrough. Coaxial counterbores 38 communicate with the 
apertures 36. The counterbores 38 accommodate the insulation 16 of wires 
inserted into the connectors. Similarly, the apertures 36 allow entry of 
the stripped ends of conductors 14 into the enclosure. The apertures are 
sized according to the gauge of wire to be connected. The apertures may 
all be of the same size or there could be different sized apertures in the 
same connector for connecting wires of different gauges. The insert guides 
the wires into the clip, as will be described below. Also, the insert 
provides insulation which prevents shorting or arcing. 
The housing further includes attachment means which allows stacking or 
interconnecting of multiple, like connectors. In the illustrated 
embodiment the attachment means comprises a pair of cooperating, elongated 
male pins 40 located on the top wall 22 of the housing. The pins are 
connected at the open side of the body member by a web 42. The web 
overlies the opening 34 in the top wall and engages the tab 32 of the 
insert to retain the insert in place. On the bottom wall 24 there are a 
pair of cooperating female pins 44, which together define a socket into 
which the pins 40 of a second, like connector fit. As best seen in FIGS. 3 
and 4 the net effect of the pins 40 and 44 is that of a dovetail 
arrangement. A web 46, similar to the web 42, spans the lower opening 34 
to retain the lower tab 32. 
Turning now to FIGS. 5-7, a one-piece conductive clip, shown generally at 
48, is disposed inside the enclosure formed by the housing 18. The clip 
has first and second portions 50 and 52, respectively. The first portion 
is a flat plate having its free end trapped between two of the lugs 27 and 
the bottom wall 24. It will be noted that an extra set of lugs is provided 
so that the clip may be inserted with the first portion adjacent either 
the top or bottom wall. 
The second portion 52 of the clip is a generally U-shaped piece having legs 
54 and 56 separated by a bight 58. Leg 56 is connected to the first 
portion 50 of the clip. It extends upwardly adjacent the apertures 36 in 
the insert 30. Holes 60 in the leg 56 permit passage of conductors 14 into 
the housing enclosure. The bight 58 and leg 54 are cantilevered from the 
upper end of leg 56. The leg 54 defines a spring which is normally located 
opposite the apertures 36 and holes 60. This is the position shown in 
solid lines in FIG. 5. When conductors are inserted into the housing they 
will necessarily impinge on the spring defined by leg 54. Further 
insertion of the conductors will cause the spring to deflect to the 
position shown in dotted lines in FIG. 5. This flexing of the spring is 
possible because the first portion 50 of the clip is held fixed by the 
lugs 27. Thus, the conductors 14 separate the first and second portions of 
the clip from their normal, relaxed positions. This generates a clamping 
force, imparted by the spring to the conductors. The clamping force 
retains the conductors in the housing. 
The leg 54 has a pair of longitudinal slits 62 which define individual 
fingers 64 on the free end of the leg. The fingers have V-shaped notches 
66 which assist in gripping the conductor inserted underneath a finger. 
Further enhancement of the clamping force is provided by the construction 
of the clip. The clip may be a bimetallic part which when heated by 
electrical current expands in a manner which increases the clamping force. 
That is, the leg 54 tends to expand toward the first portion 50. This 
raises the clamping force on the conductors. The clip may be formed from a 
strip made of about one half steel and one half copper alloy, with the 
copper on the inside and the steel on the outside, as shown in FIG. 5. 
Alternatively, the clip may be made of a copper alloy instead of the 
bimetal. A suitable copper alloy has been found to be: Nickel 3.0%; 
Silicon 0.65%; Magnesium 0.15%; and Copper remainder. Another possible 
alloy is: Nickel 12%; Aluminum 2%; Manganese 0.35%; Magnesium 0.2%; and 
Copper remainder. Additional possible materials for the clip are #510 
phosphor bronze and two types of spring temper brass. 
The use of the connector is as follows. The stripped ends of wires ar 
inserted into the counterbores 38 of the insert 30. The wires are pushed 
in until either the conductor 14 bottoms on end wall 26 or the insulation 
16 bottoms in a counterbore. As the conductor moves into the enclosure, it 
contacts one of the fingers 64, moving it counterclockwise, as seen in 
FIG. 5. As additional conductors are inserted they similarly engage a 
finger of the leg 54. Since the clip 48 is a single part, the conductors 
are shorted and electrical connection is established. The notches 66 grip 
the conductor 14 to retain it in the housing. 
Whereas a preferred form of the invention has been shown and described, it 
will be realized that alterations may be made thereto without departing 
from the scope of the following claims. For example, the number of 
apertures 36 and corresponding holes 60 in the clip 48 could be greater to 
accommodate an increase in the number of wires insertable into a single 
connector.