This invention relates generally to cable splice cases and, more particularly, to expansion rings for splice case end plates.
Communication and electrical cable splices are protected from environmental damage by housing in cable splice cases, which protect from moisture, humidity, corrosive environments and the like. Some cable systems employ compressed air in the cables and splice cases to prevent moisture intrusion against the air flow. In these systems, for efficiency and economy, minimizing air loss is advantageous. Thus, cable splice cases can be airtight as well as environmentally sealed.
A variety of cable splice cases are known. Typically, the cases include a cylindrical housing for containing the cable splice, and a pair of circular end plates that fit tightly into the ends of the housing, providing airtight, environmental seals. In one design, the splice case is formed from two half-housings that are installed over suitably prepared end plates.
Communication and electrical cables that extend through openings in the end plates must also be airtight and environmentally sealed against the openings. Various means of sealing are known including compressible collars, O-rings and sealing tape.
A damaged cable line is usually repaired by replacing the entire damaged section of cable lying between two contiguous splice cases. The splice cases are placed in separate manholes. Usually, emergency work restores service to customers before the damaged cable line has been replaced. To replace the cable, both splice cases must be opened and a new section of cable installed. When replacement takes several days, the splice cases must be closed and sealed at the end of each working day. During repair, both damaged and new sections of cable are present and both must be protected by the contiguous splice cases. If the original splice cases are too small to accommodate both sections, larger splice cases must be employed.
Currently, switching to a larger splice case involves replacing both end plates with new, larger end plates. Preparing a new end plate to receive cables in an airtight and environmentally sealed manner is a time consuming task. Further, after repair and removal of the damaged section, the original splice case (or one of similar dimensions) must be reinstalled due to space limitations in the manhole. Thus, both larger end plates must be changed back to smaller end plates, consuming additional preparation time. Because two contiguous splice cases are involved, and four new end plates are prepared per splice case, in all, eight new end plates must be prepared during cable replacement.
Another problem caused by switching end plates back and forth is further damage to the cables. The process of preparing cables to form air tight, environmental seals can introduce cable deformities, as can the process of installing and removing end plates from around cables. Cable deformities increase the chance of air leaks.
The present invention relates to a device that eliminates the need to replace one original end plate of each splice case when repairing a damaged cable line, thus decreasing the time required for cable replacement and reducing possible cable damage during end plate preparation.
The present invention provides an expansion ring for expanding the perimeter of a splice case end plate. The ring comprises two face plates and a rim connected to and separating the face plates, with an aperture extending through the face plates. The ring is designed to fit around the perimeter of the end plate by locating the end plate in the aperture, forming an air tight, environmental seal between end plate and ring. Once the ring is in place, a larger splice case housing can be installed over the expanded end plate.
In a particular embodiment, the expansion ring is annular, comprising two round face plates and a rim in between, with a round aperture extending through the face plates. The ring is designed to expand the diameter of round end plates typically used in cylindrical splice cases.
Also provided are a method of expanding the perimeter of a splice case end plate and a method of installing a larger splice case. Both methods utilize the expansion ring of the present invention.
Further, the present invention provides a splice case having two end plates and a housing, in which at least one end plate is an expanded end plate formed by placing an expansion ring around a smaller perimeter end plate. The housing and two end plates form an air tight, environmentally sealed chamber.
More particularly, a method is provided of repairing a damaged cable line wherein a damaged cable extends through a first end plate on one side of a splice case to an undamaged cable extending through a second end plate on the opposite side of the splice case in which a plurality of individual wires of the damaged cable are spliced a plurality of individual wires of the undamaged cable in the splice case. The method comprises: (1) opening the splice case to expose the spliced wires; (2) bringing the end of a replacement cable through a temporary, third end plate larger than said first end plate and which is formed with sufficient openings to separately encase the damaged cable, the undamaged cable, and a replacement cable; (3) placing an expansion ring on the second end plate, the expansion ring having a diameter substantially the same as the diameter of the third end plate and formed with an aperture therethrough adapted to receive the second end plate in an environmentally sealing relationship; (4) disconnecting some, but not all, of the spliced wires; (5) placing the damaged cable, undamaged cable partially connected to the damaged cable, and replacement cable partially connected to the undamaged cable in a temporary splice case of a size to form with the third end plate and expansion ring, and environmentally sealing relationship; and (6) thereafter, opening the temporary splice case, finishing splicing remaining wires to completely remove the damaged cable and completely connect the replacement cable to the undamaged cable, then replacing the third end plate with the first end plate, or with a same size substitute therefor, removing the expansion ring, and placing the undamaged cable connected to the replacement in the original splice case, or in a same size substitute therefor, in an environmentally sealing relationship.