Metal working – Method of mechanical manufacture – Electrical device making
Reexamination Certificate
1999-01-11
2001-05-15
Young, Lee (Department: 3729)
Metal working
Method of mechanical manufacture
Electrical device making
C029S857000, C029S861000, C029S862000, C029S863000, C029S865000, C029S866000, C029S867000, C029S745000, C029S747000, C029S748000, C029S751000, C029S753000, C029S755000, C439S096000, C439S098000
Reexamination Certificate
active
06230406
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates generally to devices for implementing a ground connection between a metallic sheath of a cable and a common ground point. More particularly, the present invention relates generally to devices for providing a water-proof ground connection between a metallic sheath of a cable and a common ground point.
Buried telecommunications cables often utilize a distribution pedestal for housing cable ends and splices. These pedestals provide easy access to the cable ends without excavation of the buried cables for splice installations, maintenance and troubleshooting. However, such pedestals are not a closed environment and rain run-off or other ground water may enter the splice. This moisture will contribute to the corrosion of the copper conductors and metallic sheath leading to a degradation of the mechanical integrity and the electrical characteristics of the cable. Generally, the splices are made watertight to prevent the introduction of water. The splices may be made watertight by encapsulating or flooding the splice area with a urethane or gel compound. Alternatively, the splice bundle may be enclosed in a heat shrinkable enclosure.
If the cable includes a metallic sheath, the sheath must be electrically bonded to the pedestal housing. The housing, in turn, should be grounded. Consequently, a grounding conductor, typically a number 6 AWG conductor, must exit the encapsulated/housed splice for connection to the pedestal housing. In geographic areas which are subject to ground freeze/thaw cycles, there is relative movement between the pedestal housing and the cables since the cables are usually buried below the frost line and the pedestal housing is buried at least partially above the frost line. If the ground connection is not sufficiently flexible to accommodate such relative movement or roadside vibration, the watertight seal will be jeopardized. A solid number 6 AWG conductor is relatively stiff and is too inflexible to properly accommodate relative motion between the pedestal housing and the splice. If a stranded number 6 AWG conductor is used, moisture can wick into the space between the individual conductors and enter the splice.
One conventional grounding device mounts a solid number 6 AWG conductor to a stranded number 6 AWG conductor via a butt splice. The solid conductor is mounted to the cable sheath and extends out of the encapsulated/housed splice. The stranded conductor provides sufficient flexibility to allow relative movement between the splice and the pedestal housing. Although both conductors are number 6 AWG, the outside diameter of the stranded conductor is greater than that of the solid conductor. Typically, a connector having one end which is sleeved to reduce the inside diameter is used to ensure that connector is properly crimped. Such connectors are relatively expensive. In addition, the assembly worker must identify which end of the connector has been sleeved and orient the connector to insert each conductor into the proper end of the connector. Consequently, it takes a relatively long time to assemble each grounding device even though the device has a relatively simple design.
In addition to the difficulty of properly connecting two different diameter conductors, crimped connections are subject to degradation of their mechanical and electrical properties if they do not provide a “gas tight” connection. A crimped wire connection is “gas tight” if all of the individual conductors of a stranded conductor are compressed together leaving no voids for air and moisture to enter. For a solid conductor, the connection is “gas tight” if the conductor cannot rotate within the connector. If the connection is not “gas tight” moisture will enter the connection causing corrosion which degrades the mechanical connection and electrical properties of the connection. It is especially difficult to insure that both connections in a butt splice are “gas tight” when a solid conductor is joined to a stranded conductor and the conductors have different diameters.
SUMMARY OF THE INVENTION
Briefly stated, the invention in a preferred form is a flexible bond harness which includes a flexible ground subassembly and a rigid ground subassembly which are joined together by a barrel connector. The flexible ground assembly has a first terminal connector which is mounted to the distal end portion of a substantially flexible conductor and the rigid ground assembly has a second terminal connector which is mounted to the distal end portion of a substantially rigid conductor. The outside diameter (Df) of the flexible conductor is greater than the outside diameter (Dr) of the rigid conductor. The longitudinally extending barrel connector has a substantially uniform thickness, first and second side walls and a base. The barrel connector is divided into first and second segments extending from the first and second ends, respectively, to a position intermediate the first and second ends. The proximal end portion of the flexible conductor is positioned within the first segment and the proximal end portion of the rigid conductor is positioned within the second segment. The first and second segments of the barrel connector are simultaneously crimped onto the flexible and rigid conductors, respectively, forming a bond which prevents relative motion between the barrel connector and the flexible and rigid conductors.
The bond is fashioned, in part, by a cold weld connection which is formed between the longitudinally extending leading edges of each side wall of the barrel connector conductor. The bond is also fashioned by mechanical engagement between the flattened base of the barrel connector and a flattened surface of the conductor. A similar bond is formed between the mounting portion of each terminal connector and the distal end portion of the rigid or flexible conductor. That is, the longitudinally extending leading edges of each side wall of the mounting portion forms a cold weld with the conductor and the flattened base of the mounting portion mechanically engages a flattened surface of the conductor.
The flexible bond harness is manufactured utilizing a pair of work stations. The first work station has a first die and an associated first punch for crimping the portion of a barrel connector containing the stranded conductor and a second die and an associated second punch for crimping the portion of the barrel connector containing the solid conductor. The second work station contains either a first die and punch or a second die and punch. The first and second dies each include an inner surface having a profile and defining a cavity. The profile of the first die is substantially identical to the profile of the second die. The first and second punch each have a punch segment having an intermediate surface and first and second bar segments which extend upwardly from the intermediate surface to an upper surface. The intermediate surface and upper surface of each punch define a height where the height of the second punch is greater than the height of the first punch.
The barrel connector has a substantially uniform thickness and first and second connector segments. Each of the connector segments has first and second side walls and a base. The barrel connector is positioned in the first work station such that the first connector segment is positioned intermediate the first die and the first punch and the second connector segment is positioned intermediate the second die and the second punch. A second end portion of the flexible conductor is positioned in the first connector segment and a second end portion of the rigid conductor is positioned in the second connector segment.
The work station press is activated, causing the first and second punches to be moved toward the first and second dies, sequentially causing the following steps to occur: a) the first and second bar segments of the second punch engage the second connector segment; b) the first and second side walls of the second connector segment slide on the inner surface of the second die to commenc
Auclair John W.
Balfour William J.
Alix Yale & Ristas, LLP
Electric Motion Company, Inc.
Kim Paul D.
Young Lee
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