Abstract:
Solderless electrical connector receives solid wire by rolling wire progressively into a channel between two elongate plate-like members formed from an integral base against which the wire is rolled. At least one of the plate-like members yields resiliently to accommodate a wide range of wire sizes and further maintains contact force on the terminated wire.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to electrical connectors for solderless wire termination, particularly to a connector adapted to have the wire axially channeled in the slot. 
     Electrical connectors having wire-receiving slots are well known. See, e.g., U.S. Pat. No. 4,116,522. Most such connectors employ a metal plate with a slot profiled therein, or employ a plate folded along an axis perpendicular to an elongate aperture in order to form a slot. See, e.g., U.S. Pat. No. 4,261,629. The slot in this prior art is intended to receive a wire inserted laterally of the wire axis. It is also known to insert a wire into a groove by pressing a wire therein parallel of its axis as in U.S. Pat. Nos. 3,038,958 and 3,777,051, as well as to press a wire into a slotted plate parallel of its axis as in U.S. Pat. Nos. 4,173,388 and 4,225,208. The latter two patents disclose laying the wire to be terminated against a slot in a plate and forcing the wire progressively into the slot from a throat portion to a narrower wire-contacting portion of the slot. The wire has its sides sheared along the axis of the wire and is coined or mashed into the slot. The slot is substantially non-yielding and the termination is in the form of a crimp. 
     SUMMARY OF THE INVENTION 
     The present invention relates to a roll-in-slot type terminal employing two adjacent elongate plate-like members having edges forming a channel therebetween and lying against a base portion from which the elongate members are formed. In one embodiment, a metal plate is folded against itself at parallel bights to form elongate plate-like members in the form of laps with a channel therebetween. The plate is notched along one of the fold lines so that one of the laps has a much shorter bight and extends toward the other lap as a cantilever beam. The channel is open at one end and converges into a wire-receiving portion where the distance between laps decreases to less than the diameter of the smallest wire to be terminated. The cantilever beam flexes as a wire is rolled into the wire-receiving portion. In an alternative embodiment, the elongate plate-like members are stamped from the plate leaving apertures therein. 
     An object of the invention is to provide a single connector suitable for terminating a large range of wire sizes. 
     An object is to provide a high compliance termination with a large wire contact area. 
     Another object is to provide a roll-in type termination where the surface against which the wire is rolled is integral with the terminal. 
     A related object is to provide a low-profile terminal which terminates the wire parallel to its axis. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective of the terminal. 
     FIG. 2 is a perspective of the terminal as a wire is placed for termination. 
     FIG. 3 is a perspective of a terminal with a terminated wire. 
     FIG. 4 is a perspective of the terminal in strip form prior to forming. 
     FIG. 5 is a perspective of an alternate embodiment of the terminal. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1 depicts a connector 10 with a wire-terminating portion or terminal 12 as taught by the present invention and a mating portion 13. The mating portion 13 as shown herein is in the form of a spade-receiving terminal but could also be formed as a socket or other terminal for use with the present invention. The terminal 12 has a base portion 14 which extends from a first end 18 to a second end 19. The terminal 12 is folded against itself at first bight 23 to form first lap 22 which lies against the base portion 14. The terminal 12 is folded against itself at second bight 29 parallel to first bight 23 to form second lap 28. The laps 22, 28 have respective facing first and second edges 24, 30 which define a wire-receiving channel 15 therebetween. The channel 15 has an entry portion 16 at first end 18 and converges to a wire-receiving portion 17 toward second end 19. The edges 24, 30 converge gradually until they meet, at which point the second lap 28 ends and the first lap 22 has an overlap 25 which extends beyond the channel 15. 
     The terminal 12 has a notch 34 along the fold line of bight 29, so that bight 29 is foreshortened as compared to bight 23 and the second lap 28 extends from the bight 29 toward first lap 22 in the form of a cantilever beam 32. The beam is profiled opposite second edge 30 by a rear edge 31 which extends from the end of the beam to the apex 33 of notch 34, which is also referred to as a point 33 intermediate ends 18, 19 of the base portion 14. 
     FIG. 2 shows a wire 6 laid against channel 15 with roller 5 poised to roll the wire 6 therein. The wire lies in entry portion 16 against the base portion 14 of the terminal 12, and the roller 5 keeps the wire 6 against the base portion 14 while the roller 5 advances and the wire 6 causes the cantilever beam 32 to flex as the channel 15 conforms to the wire 6. Insofar as the beam 32 flexes to accommodate the wire, a wide range of wire sizes, e.g., 1 mil to 20 mils, can be terminated using a single size terminal. The elasticity of the cantilever beam 32 is determined by the arm length and the cross-section area, which in turn is determined by the thickness of the metal and the width between the second edge 30 and rear edge 31. Additional stiffness is designed in where it is desired to strip plastic or varnish insulation from the wire being terminated. It should be noted that, while the wire is not cut and mashed as it is in the prior art, some scraping along the axis of the wire does occur while it is being rolled into the channel 15. This assures good electrical contact, which is maintained by the spring force in the cantilever beam 32. 
     FIG. 3 depicts a terminated wire. The end of the wire has been trimmed as the roller 5 pressed it against overlap 25. The edges 24, 30 of the laps 22, 28 are coined slightly as is optional to help retain the wire 6 in the channel 15 against the base portion 14. 
     FIG. 4 shows the connector 10 in strip form after stamping and prior to forming. Carrier strips 36 and indexing holes 37 permit ready indexed movement through the forming dies, and the strips 36 may be used to package the connectors in reel form or transport them for additional operations such as application to a connector or wire insertion. 
     FIG. 5 depicts an alternative embodiment of the terminal of the instant invention wherein a wire-receiving channel 45 is formed between two elongate plate-like members 42, 48 which are stamped from a base portion 44. The plate-like members 42, 48 have respective facing first and second edges 43, 50 which define the wire-receiving channel 45 therebetween. The channel has a wire-entry portion 46 and converges toward a wire-receiving portion 47. Both elongate members 42, 48 are attached at both ends to the base portion 44; compliance to different wire sizes is achieved by a predetermined combination of length, width, thickness, and shape of the elongate members 42, 48. Both members 42, 48 will be resilient and thus provide the residual spring force necessary for effective wire termination. Note that the base portion 44 of the terminal is mashed or coined at 51, 52 adjacent to elongate members 42, 48 so that the elongate members 42, 48 will not collapse into the apertures below as a wire is rolled into the channel 45. 
     The above descriptions are exemplary and not intended to limit the scope of the claims which follow.