Electrical connectors – Contact comprising cutter – Insulation cutter
Reexamination Certificate
2000-12-12
2001-12-04
Ta, Tho D. (Department: 2833)
Electrical connectors
Contact comprising cutter
Insulation cutter
C439S406000, C439S407000
Reexamination Certificate
active
06325658
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an insulation-displacement terminal fitting and to a method for producing an insulation displacement terminal fitting.
2. Description of the Related Art
A known insulation-displacement terminal fitting is disclosed in Japanese Unexamined Patent Publication No. 50(SHO)-114592. This terminal fitting has a pair of side walls and inward-facing blades on the side walls. The blades cut a resin coating of a wire inserted between the blades and contact a core of the wire. Each blade is V-shaped when viewed in an inserting direction of the wire, and is formed by embossing the flat side wall with a press so that a part of the side wall is bent into the V-shape.
The V-shaped blades typically are formed by embossing the side walls with dies disposed at the locations that are specified to define the pointed contacting edges at the leading ends of the V-shaped blades. This embossing process causes the side walls to stretch and become gradually thinner toward the pointed contacting edges. Thinning at these location may cause cracks to occur at the contacting edges formed at the leading ends of V-shaped blades.
To avoid such cracks, one might consider widening the spacing between the blades by embossing the side walls to project a smaller distance. However, a terminal fitting of this design could not accommodate thin wires. One also might consider forming the insulation-displacement terminal fitting from a relatively soft material. However, this design option may cause a deformation during an insulation-displacement connection and an insufficient contact pressure. Thus either of these design options cannot solve the above problem.
In view of the above, an object of the present invention is to prevent cracks during the embossing of V-shaped blades for an insulation-displacement connection.
SUMMARY OF THE INVENTION
The subject invention is directed to an insulation-displacement terminal fitting with at least one side wall. The side wall is embossed inwardly to form at least one substantially V-shaped blade that projects from the side wall for cutting into an insulation coating of a wire and for connection with a core of the wire. At least one weakened portion is formed at and/or near portions of the blade and/or the side walls.
The weakened portions are stretched to a large degree during embossing. Thus, a stretching degree of the blades, and preferably a stretching degree of the pointed edges at the leading ends of the V-shaped blades, can be small, thereby preventing cracks in the blades, and preferably in the pointed edges of the blades.
The weakened portions may be at least partly in the form of through holes. Additionally or alternatively, the weakened portions may be at least partly in the form of recesses formed by partial thinning.
Most preferably, the weakened portions are at and/or near portions that are continuous with the blades and the side walls.
The weakened portions may be formed to extend substantially continuously over the blades and/or the side walls. More particularly, the weakened portions may extend in embossing directions, i.e. along the longitudinal extension of the blades and side walls.
The forming areas of the weakened portions extend distances in stretching directions that are larger than weakened portions that are formed either in the blades or in the side walls. Thus, the areas of the weakened portions are distorted only to a small degree, and as a result these portions can remain relatively thick.
Preferably, the insulation-displacement terminal fitting further comprises a bottom wall, and at least one slit is formed at least partly between the blade portions and the bottom wall.
The invention also is directed to a production method for producing an insulation-displacement terminal fitting. The method comprises providing an electrically conductive plate and forming at least one weakened portion at and/or near portions of the plate that will define blades and/or side walls. The method proceeds by embossing at least one portion of the plate that will define at least one side wall to form at least one substantially V-shaped blade projecting from the side wall for cutting into an insulation coating of wire so that the blade connects with a core of the wire.
According to a preferred method, the plate is provided such that the portions of the plate that are to be embossed have a substantially constant thickness.
Most preferably, the weakened portions are provided at least partly in the form of through holes and/or of recesses that are formed by partial thinning.
These and other objects, features and advantages of the present invention will become apparent upon reading of the following detailed description of preferred embodiments and accompanying drawings. It should be understood that even though embodiments are described separately, single features may be combined to additional embodiments.
REFERENCES:
patent: 3867005 (1975-02-01), Hoppe, Jr.
patent: 4040702 (1977-08-01), McKee et al.
patent: 4057314 (1977-11-01), Mathe et al.
patent: 4427251 (1984-01-01), Mathe et al.
patent: 4940425 (1990-07-01), Hass et al.
patent: 5549483 (1996-08-01), Hotea
patent: 6012942 (2000-01-01), Volstorf
patent: 0 722 197 (1996-07-01), None
patent: 1 490 197 (1977-10-01), None
Casella Anthony J.
Hespos Gerald E.
Sumitomo Wiring Systems Ltd.
Ta Tho D.
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