Electrical terminals are used in a wide variety of applications for connecting and/or terminating insulated electrical wires. An insulated electrical wire typically includes a center conductor (which may be solid or stranded) surrounded by an outer sheath or cover of insulating material such as plastic. With some terminals for insulated wires, the insulating covering is removed to expose the center conductor, and at least portions of the terminal are crimped onto the exposed conductor to establish an electrical connection therewith, while other portions of the terminal may be clamped onto the outer insulating covering to provide a type of strain relief for the wire. This type of terminal most often is used to terminate the very end or tip of an insulated electrical wire. It can be understood that a separate fabricating step is required to remove the insulating covering and expose the center conductor.
In order to eliminate the step of insulation removal, insulation displacement terminals (IDT) or insulation piercing terminals have been designed. As is well known, these types of terminals include portions which cut through or pierce the outer insulating covering of the insulated electrical wire to establish an electrical connection with the center conductor. One type of insulation displacement terminal includes a transverse wall having a slot into which the insulated wire is forced. The edges of the slot cut through the insulation of the wire. Other insulation displacement terminals have pointed prongs, discrete serrations, detents, or the like which are forced through the insulating covering of the wire, such as during a crimping operation which also performs a secondary function of providing strain relief for the wire. These types of insulation displacement terminals most often are used in connecting or terminating insulated electrical wires wherein the outer insulating covering of the wires is relatively soft and easy to penetrate or cut.
On the other hand, a type of insulated electrical wire commonly called a "magnet wire" is used in a variety of applications which include wire windings, such as motors, generators and transformers. Instead of using a typical insulated wire which has a relatively soft plastic outer insulating covering, the insulation of a magnet wire is a layer of lacquer, varnish or epoxy. The resulting insulating coating is thin and relatively hard. Typical insulation displacement prongs, detents or the like simply are not sufficiently robust to cut through or pierce this hard coating of magnet wires.
One approach to terminating magnet wires or other electrical wires having relatively hard outer coatings is simply to provide a very heavy or thick terminal which literally is "crushed" (versus being crimped) onto the wire to literally smash through the hard coating. Such relatively massive terminals not only involve excessive materials, but their fabrication is more expensive and problems can occur in damaging the terminated wires, themselves, because of the relatively large forces required to crush the sizable terminal.
The present invention is directed to a much simpler and inexpensive terminal, particularly a crimp terminal, which is effective for piercing the hard coating of magnet wires and making electrical contact with the conductor of the wire.
USPTO Backgrounds
USPTO Backgrounds