Patent Publication Number: US-5833488-A

Title: Bladed wire connector and method for forming same

Description:
TECHNICAL FIELD 
     This invention relates to a method and apparatus relating to wire connectors and more particularly to a wiring connector having blades that effectuate a connection with a coated wire. 
     BACKGROUND ART 
     As is well known in the art, wires must be connected at their ends to other wires or electrical devices. Typically, coated wires are stripped of their insulation to make electrical connections with connectors. The connector is then electrically connect to another connector, an electrical component or another wire. However, stripping the wire is time consuming and may cause defects if the wire is damaged during the stripping process. 
     DISCLOSURE OF THE INVENTION 
     It is an object of the invention to create a connector that electrically connects with a coated wire with a minimum of time and effort. 
     It is a further object of the invention to create a connector that, while being formed, securely engages a wire. 
     It is a still further object of the invention to electrically connect with a coated wire without stripping the wire. 
     According to the invention, a connector is provided having a set of spaced bladed surfaces that cooperate to penetrate the coating of a wire to make electrical contact with the wire while the connector is bent therearound. According to a feature of the invention, the blades are circumferentially located about the wire at approximately 120° intervals. According to a further feature of the invention, the connector has a plurality of sets of blades. 
     Further according to the invention, a method of forming a connection between a wire having a coating and a connector is disclosed having the steps of extending a first, a second and a third blade from a connector body, the second blade disposed between the first and third blades, and bending the body about a portion between the first and second blades and about a portion between the second and third blades so that the blades engage the wire through the coating. 
     These and other features of the present invention can be best understood from the following specification and drawings, of which the following is a brief description. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a plan view of the connector of the invention. 
     FIG. 2 is a transverse view of the connector of FIG. 1 showing blades in position to engage a wire. 
     FIG. 3 is a cutaway view of the connector of FIG. 1 showing blades engaging a wire. 
     FIG. 4 is a view showing edges of the connector penetrating the coating and engaging a wire. 
     FIG. 5 is a further embodiment of the connector of the invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1 shows a plan view of the connector 10 of the invention. The connector has: a body 12; three sets of blades protruding therefrom, a first end blade 14, a middle set of blades 16 and a second end blade 18; and a plurality of U-shaped cut-outs 20 for receiving the end blades 14, 18, as will be discussed infra. According to a further feature of the invention the connector may have a tab 22 and slot 24 (see FIG. 5) that minimize spring-back after the connector is formed as will be discussed infra. 
     The connector body 12 is an electrically conductive, flat, rectangular, bendable blank material as is known in the art. The body has a first end portion 26, a central portion 28, and a second end portion 30. The first and second end portions each have an M-shaped cutout 32. The M-shaped cutouts 32 define the first and second end blades 14, 18, each blade having a central arc 34 for gripping a wire strand (s) 36 and penetrating its coating 38 as will be discussed infra. The U-shaped cut-outs 20 define openings that receive a blade 14 or 18 from the other end portion as will be discussed infra. The central portion 28 has a pair of H-shaped cutouts 42 that define the middle set of blades 16, each blade having a central arc 34 for gripping a wire as will be discussed infra. A first axis 44 passes along the central arc in the middle set of blades. A second axis 46 extends between each end portion and the central portion. Each end portion has a coined edge 48 to allow the connector to grip the wire after penetrating the coating if the connector is crimped (see FIG. 4). 
     To attach the connector 10 to a strand(s) 36, the blades are bent 90° along lines 40 in the same direction as the other blades (e.g., either into or out of the page). The strand is disposed along axis and nests within the central arcs 34. The body is then bent in two sections along second axes 46 (see FIG. 2) thereby driving the blades through the wire coating 38 into contact with the strand(s) 36 (see FIG. 3). Because the end blades 14, 18 are offset from the middle set 16, the blades do not interfere with each other while gripping the wire. The offset also minimizes the probability that the wire is stripped if the wire and the connector are subjected to a certain pulling force, i.e., the blades do not cut the wire coating around the circumference of the wire in one location. Because the end blades are received within the U-shaped cutouts 40 on each other end portion of the body, the body also does not interfere with the blades contacting the wire. The blades engage the wire in several sections at approximately 120° intervals to ensure electrical connection with the wire and to make it difficult to disconnect the wire from the connector. To further ensure electrical or mechanical connection with the wire, the coined edges 48 are crimped through the wire coating into contact with the wire, thereby completing construction of the connection (see FIG. 4). 
     According to an embodiment of the invention as shown in FIG. 5, the body may have a tab 22 disposed at one end thereof. The tab 22 is inserted into slot 24 if the body is bent to minimize the possibility that the connector springs away from the wire. As further provided in FIG. 5, the body has two blades in each end set of blades and two sets of U-shaped cut-outs to receive each blade if the body is bent to maximize contact with a wire. 
     The present invention has several advantages. By utilizing blades to contact the wire, stripping is eliminated and production efficiencies are realized without damaging the wire. By utilizing a plurality of offset blades, the wire is gripped securely minimizing the risk of stripping the coating from the wire. By providing a locking tab, spring back after crimping is minimized. 
     Although the invention has been shown and described with respect to a best mode embodiment thereof, it should be understood by those skilled in the art that the foregoing and various other changes, omissions, and addition in the form and detail thereof maybe be made therein without departing from the spirit and scope of the invention. For instance, the number of blades at the middle portion or either end of the body may vary depending on the amount of grip strength and electrical contact required.