Transformer tap connector

A metal piercing staple for piercing, securing and making electrical contact between a pair of wires in the form of a substantially U-shaped piece of metal having sharp ends and a plurality of metal piercing teeth depending from the U-shaped piece of metal between the sharp ends.

FIELD OF THE INVENTION 
This invention relates to an electrical connector for piercing, securing 
and making electrical contact between a pair of wires and it relates more 
particularly to a connector for making a transformer tap connection. 
BACKGROUND OF THE INVENTION 
There have been no novel methods of making transformer tap connections 
without existing welding practices which is a problem when joining 
dissimilar metals other than cold pressure welding which is limited to the 
combined metal thickness of the tap lead and the coil conductor. Even with 
cold pressure welding, the insulation must be removed from both the tap 
lead and the coil conductor and both must be free from metal oxides to 
assure a sound electrical joint. Mechanical connections, such as crimping, 
create a bulge in the transformer coil which is not desirable. 
It would be desirable to utilize a staple like connector with penetrating 
teeth to penetrate both the tap lead and the coil conductor with the 
insulation system still in tact assuring a solid electrical connection. By 
using the staple like connector only to penetrate the top and bottom of 
the conductor joint, any bulge in the transformer coil itself would be 
minimized. Such a staple like connector would be suitable for joining 
dissimilar metals such as copper to aluminum or aluminum to copper as well 
as joining like metals. 
SUMMARY OF THE INVENTION 
It is an object of the invention to provide a metal piercing staple for 
piercing, securing and making electrical contact between a pair of wire 
comprising a substantially U-shaped piece of metal and having sharp ends 
and a plurality of metal piercing teeth depending from the U-shaped piece 
of metal between the sharp ends. 
In accordance with the present invention there is provided an electrical 
connector for piercing, securing and making electrical contact between a 
wire having a conductor and outer insulation and a flat wire having a flat 
conductor and outer insulation. The connector comprises a substantially 
U-shaped metal body having a back and a pair of legs depending therefrom, 
the legs being spaced apart a distance at least as great as the width of 
the flat wire. A plurality of metal piercing teeth depend from the back 
intermediate the pair of legs, the teeth having a length greater than the 
thickness of the flat wire and adequate to pierce the flat wire conductor 
and outer insulation and penetrate the outer insulation and conductor of 
the first-named wire so as to make electrical contact between the 
conductor and the flat conductor. The pair of legs have a length and shape 
for penetrating the outer insulation and conductor of the first-named wire 
for securing the flat wire and the first-named wire together and 
maintaining electrical contact between the conductors of the wires. In the 
preferred embodiment of the invention the ends of the pair of legs have 
barb structure for resisting removal of the legs from the penetrated 
position thereof in the first-named wire.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to FIGS. 1 and 2 there is illustrated an electrical connector 10 
embodying the present invention. As shown in FIG. 1 the connector 10 
comprises a substantially U-shaped metal body having a back portion 11 
with a pair of legs 12 depending therefrom. The legs 12 have sharp ends 
12a in the form of barbs and the back 11 has a plurality of metal piercing 
teeth 13 depending therefrom intermediate the pair of legs. 
As shown in FIGS. 3 and 4 the electrical connector 10 is adapted for 
piercing, securing and making electrical contact between a wire 14 having 
a conductor 14a and outer insulation 14b and a flat wire 15 having a flat 
conductor 15a and outer insulation 15b. As shown in FIG. 3 the legs 12 are 
spaced apart a distance at least as great as the width of the flat wire 
15. The plurality of metal piercing teeth 13 depending from the back 11 
intermediate the pair of legs 12 have a length greater than the thickness 
of the flat wire 15 and adequate to pierce the flat wire conductor 15a and 
outer insulation 15b and penetrate the outer insulation 14b and conductor 
14a of the wire 14 so as to make electrical contact between the conductor 
14a and the flat wire conductor 15a. As shown in FIGS. 3 and 4 the pair of 
legs 12 have a length and shape for penetrating the outer insulation 14b 
and conductor 14a of wire 14 for securing the flat wire 15 and the wire 14 
together and maintaining electrical contact between the conductors 14a and 
15a respectively of the wires 14 and 15. As shown in FIG. 3 there ends of 
the pair of legs 12 have barb structure 12a for resisting removal of the 
legs 12 from the penetrated position thereof in the wire 14. 
The connector 10 is made from a suitable metal and preferably one having 
adequate strength to enable the teeth to pierce the flat wire conductor 
15a and outer insulation 15b of the flat wire 15 and to penetrate the 
outer insulation 14b and conductor 14a of the wire 14. The metal from 
which the connector 10 is constructed also should have adequate strength 
so that the legs 12 will penetrate the outer insulation 14b and conductor 
14a of the wire 14 for securing the flat wire 15 to the wire 14 and 
maintaining electrical contact between the conductors 14a and 15a of the 
wires 14 and 15. An example of a suitable metal from which to construct 
the connector 10 is plated hard copper to eliminate oxidation of the 
copper or steel plated with an electrical conductive coating. 
From the foregoing it will be seen that the connector 10 of the present 
invention is particularly suited to making transformer tap connections by 
connecting the tap lead and the coil conductor together with the 
insulation system still in tact assuring a solid electrical connection. 
Any bulge in the transformer coil itself is minimized since the connector 
10 is only used to penetrate the top and bottom of the conductor joint. 
The connector 10 of the present invention is not only suitable for joining 
dissimilar metals such as copper to aluminum or aluminum to copper but is 
also suitable for joining similar metals as well as metals of varying 
thickness. 
While the present invention has been described and illustrated particularly 
in connection with making transformer tap connections, it will be 
recognized that the connector of the present invention is also suitable 
for making electrical connection between other types of electrical 
conductors.