Optical waveguides – Optical fiber bundle
Reexamination Certificate
1999-05-12
2001-01-30
Phan, James (Department: 2872)
Optical waveguides
Optical fiber bundle
C385S100000, C385S147000
Reexamination Certificate
active
06181857
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to optical fiber telecommunications cables. More particularly, the present invention relates to a method for accessing an optical fiber in a sheath typically disposed in a telecommunications cable.
2. Description of the Prior Art
Telecommunication cables employing optical fibers are widely used in the telecommunications industry because such optical fibers provide relatively wide bandwidth and low noise operation. Telecommunications cables employing multiple optical fibers are used for a variety of applications including long distance telephone communications, interexchange telephone applications, and other telephony and data transmission applications. Cables containing multiple optical fibers are also being used by cable television networks in the place of traditional coaxial cables containing metallic conductors to provide the bandwidth necessary to support services such as near real-time, on-demand video to the home.
A typical optical fiber cable is formed by one or more cores which contains a plurality of optical fibers and an outer protective jacket surrounding the one or more cores. There are numerous issued U.S. patents that describe various, specific configurations for such cables. In a typical commercially available loose-tube type optical fiber cable, a series of plastic buffer tubes or sheaths are stranded around a central support member in one or more concentric layers. In most commercially available cables, the plastic buffer tubes are provided with a unique color for identification purposes. Also, each of the fibers in a buffer tube are provided with a unique color-coded coating thereon to enable identification of a particular individual fiber from the other fibers within a colored buffer tube of the cable. The color-coding scheme is important when fibers are to be dropped out of the cable to provide a local optical fiber branch.
Cables which are useful in the cable television field typically have a relatively small number of grouped fibers, typically three or four fibers, which are identified, accessed and connected at a drop point. In addition, a large number of spaced apart drop points are typically provided along the length of the cable to enable fibers to be dropped, as required. When a fiber is to be dropped, access to a fiber protected by one of the buffer tubes in the cable is made at a drop point. Typically, access is made by cutting into the outer jacket and using buffer tube cutting or slitting tools to remove a portion of the buffer tube. The use of such tools is necessary for some cable designs because the buffer tube material is tough. On the other hand, some buffer tube or sheath materials are relatively soft and tools are not required. Whether a buffer tube slitting tool is necessary or not, it is important that during the procedure of accessing an optical fiber, other optical fibers are not damaged. Also, once the optical fiber is accessed, it is important to protect the remaining optical fibers in a manner similar to the type of protection provided by the buffer tube. Because the prior methods for accessing the optical fibers typically remove a portion of the buffer tube, the portion of the tube or sheath is no longer available to provide protection to the remaining fibers.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a method for accessing an optical fiber contained in an optical fiber buffer tube or sheath. It is another object of the present invention to provide a method for accessing an optical fiber which leaves the buffer tube or sheath accessed substantially in-tact after access has been made.
The present invention is designed to meet the foregoing objectives by providing a method for accessing a fiber from a bundle of fibers disposed in a sheath. The method comprises several steps, including: cutting the sheath circumferentially at a leading position and cutting the sheath circumferentially at a trailing position to divide the sheath into a leading section, a mid-section and a trailing section; spreading the cut sheath along the axis of the sheath between the leading section and the mid-section to create a first access opening; cutting a fiber to be accessed at the first access opening so as to create an accessible fiber portion and a severed fiber portion; pushing the leading section and mid-section together to close the first access opening; spreading the cut sheath along the axis of the sheath between the mid-section and the trailing section to create a second access opening; pulling the accessible fiber portion from the mid-section of the sheath so that the accessible fiber portion extends out of the second access opening; and pushing the mid-section and trailing section of the sheath together to close the second access opening wherein the accessible fiber portion is permitted to extend out of the trailing cut.
The invention will be more fully understood when reference is made to the following detailed description taken in conjunction with the accompanying drawings.
REFERENCES:
patent: 3902206 (1975-09-01), Naquin
patent: 4331379 (1982-05-01), Oestreich et al.
patent: 4746190 (1988-05-01), Oestreich et al.
patent: 5085114 (1992-02-01), DeRoss et al.
patent: 5155789 (1992-10-01), LeNoane et al.
patent: 5181268 (1993-01-01), Chien
patent: 5345526 (1994-09-01), Blew
patent: 5408564 (1995-04-01), Mills
patent: 6104846 (2000-08-01), Hodgson et al.
patent: 197 20 598 (1998-11-01), None
patent: 197 49 930 (1999-05-01), None
patent: 2 212 626 (1989-07-01), None
Emeterio Marta Garcia S.
Richter Stefan
Alcatel
Phan James
Ware, Fressola, Van der Sluys & Adolphson
LandOfFree
Method for accessing optical fibers contained in a sheath does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for accessing optical fibers contained in a sheath, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for accessing optical fibers contained in a sheath will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2552541