Electrical connectors – With insulation other than conductor sheath – Metallic connector or contact secured to insulation
Reexamination Certificate
1997-10-20
2001-02-20
Patel, T. C. (Department: 2839)
Electrical connectors
With insulation other than conductor sheath
Metallic connector or contact secured to insulation
C439S106000, C439S606000
Reexamination Certificate
active
06190212
ABSTRACT:
BACKGROUND OF THE INVENTION AND DESCRIPTION OF THE RELATED ART
The present invention is a molded plastic support usable as a premold for male contacts in an outlet plug. The support may be referred to as a bridge or male bridge since it holds male contacts in a spaced relationship.
Plugs for conventional 120 volt AC current electrical outlets usually include a pair of blades and a ground pin. The contacts are usually in a triangular relationship with a centered ground pin. In manufacture the blades and ground pin are usually crimped to individual conductor wires in a cable.
In the past wires for plugs were oftentimes machine crimped to contacts in automated systems. The wires of the cable were crimped, fed from a coil or roll on a stamping strip. The cord sets with wires crimped to the male blades and ground pin were then molded into plugs by being placed in a mold to be held in proper position.
Molding of plugs is complex. Three crimped male conductors have to be positioned in the mold for injection molding, it requires substantial labor, a substantial volume of plastic must be used in the molding and there is always the risk of wild strands.
By using the plastic support and assembly of the present invention, overmolding cycle time is reduced due to ease of loading the assembly into the mold. Overmolding compound requirement is reduced.
A less expensive overmolding compound can be used due to the plastic support retention characteristics. The plastic supports can be automatically assembled.
The plastic support allows for the crimping termination of all three contacts at once instead of the crimp termination of each of the blades and pin separately, in two different pieces of termination equipment.
The molding plastic, usually PVC, is a cost factor in the making of plugs. The labor of termination or crimping and engaging the crimped wire sets in a mold is expensive even though the crimping of the individual wires in the past was usually automated.
SUMMARY OF THE INVENTION
The present invention is a molded plastic support used in an assembly as a premold in which two flat metal male blades and/or one tubular metal male ground pin are engaged. This arrangement insures for the proper extension of the blades and/or ground pin from the front face of the plug in a molded cord set when over molded with PVC. The plastic support also provides for the proper spacing of the blades and/or a ground pin with regard to each other, both of which are specified by national standards associations.
The plastic support is cost effective because the overmolding cycle time is reduced due to ease of loading the plastic support into the mold, overmolding compound requirement is reduced, a less expensive overmolding compound can be used due to plastic support retention characteristics and plastic supports can be automatically (instead of hand) assembled.
The plastic support allows for the termination of all three contacts at once instead of terminating the blades and the pin separately in two different pieces of termination equipment.
The present invention does not have prior art problems associated with the contacts in molded plugs with high temperature, abrupt pull out and heavy weight testing, regardless of the molding compound used, as set up by national standards associations. The plastic support retains the contacts in the overmolded plastic cap rather than the contacts retaining themselves.
Blades and pins of the prior art which are overmolded without the plastic support of the present invention must be terminated separately, loaded into the production mold separately and have a greater risk of failure during testing particularly if a less expensive, softer durometer overmolding compound is used.
The plastic support of the present invention insures proper proper spacing of blades and/or a pin with regard to each other and to the pin and allows for automatic assembly where all (2 or 3) terminals are crimped at once.
The plastic support of the present invention is cost effective, reducing the cycle time required for overmolding, due to ease of engaging a loading plastic support into a mold and it reduces the plastic requirement regardless of the compound.
Once loaded with blades and/or pin terminations, automated crimping of wires from a cable to the plastic support may be done.
Basic advantages of the present invention are the speed and economy of assembly of the blades and/or pins in the plastic support, which is automatable, the ability to crimp cable wires to the male contacts in the plastic support, the ease of handling the assembly including the plastic support and the improved electrical integrity of a resulting molded plug. There is economic saving of molding plastic cost regardless of the compound used.
The present invention eliminates prior art individual crimping of wires and has the advantage of being more easily managed and saves the molding cost of the PVC plastic that is displaced by the plastic support.
Molding can be prepared in a shorter time, using less molding material.
According to the present invention, a premold assembly for a molded plastic electric outlet plug has male conductors to engage in openings in an electrical outlet female receptacle's usual spaced openings, for blades and a ground pin. The assembly has a molded plastic body with male conductors which have crimp means. There is a molded plastic body and at least two male electrical conductors, the conductors each having a first end, a body engaging portion, and a crimp end with crimp means. The plastic of the body is hard, though resilient, and has a front portion, a rear portion and at least two through openings for the conductors. The through openings are spaced apart a distance to appose the spaced openings in the female receptacle and have a span in a range between approximately 125 and 187 thousandths of an inch. The shape of the openings is selected to retain a conductor at the conductor's engaging portion. The conductors are engaged in the through openings, firmly retained in the openings, each positioned to address the openings in a female outlet receptacle.
The conductors may be blades and a round pin. The body has through openings for the conductors. The body may have more than one further opening between the front portion and the rear portion.
The through openings may have peripheral bevels on the rear portion. The blades may have strain reliefs, such as stop arms, to engage the rear portion of the body and may include a dimple to engage the front portion of the body.
The round pin may have a strain relief such as a stop arm, to engage the rear portion of the body and may have interactive means, such as a burr or D shape on the engaging portion, to engage the through hole against rotation and disengagement of the pin.
The through openings may have a span in a range between approximately 090 and 0.400 thousandths of an inch and the front portion and the rear portion of the body may define a thickness of the body in a range between approximately 0.125 and 187 thousandths of an inch.
The front portion and the rear portion of the body may also define a thickness in a range between approximately 090 and 400 thousandths of an inch.
The conductors each may have wire engaged in the crimp means and the assembly may be over molded with plastic to form a plug.
A premold assembly for a molded plastic electric outlet plug may have male conductors to engage in openings in an electrical outlet female receptacle's three spaced openings for blades and a ground pin. The assembly may have a molded plastic body with two blades and a round pin which have crimp means. The conductors each may have a first end, a body engaging portion, a stop arm and a crimp end with crimp means. The plastic of the body is hard, though resilient, and has a front portion, a rear portion and three through openings for the conductors. The through openings are spaced apart a distance to appose the spaced openings in the female outlet receptacle and have a span in a range between approximately 125 and 187 thousandths of an inch. The
Brown Donald C.
Shulman Michael Y.
Heyco, Inc.
Patel T. C.
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