Electricity: conductors and insulators – Conduits – cables or conductors – Combined
Reexamination Certificate
1999-10-21
2001-06-19
Dinkins, Anthony (Department: 2831)
Electricity: conductors and insulators
Conduits, cables or conductors
Combined
C174S07700S, C174S08400S, C174S092000, C174S093000
Reexamination Certificate
active
06248953
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to a segmented end seal for cables entering a splice case, and in particular to a segmented end seal in which the cable-receiving segments readily interlock with a central support body with a minimum of additional hardware.
BACKGROUND OF THE INVENTION
Two or more cables, such as telecommunications cables, must often be spliced together to extend or tap into a cable. The formation of a splice involves removal of the outer jacket and other layers of the cable to expose the individual conductors or optical fibers which are then individually connected to the conductors or fibers of another cable or cables. After the splice is formed, it must be protected from water and other vapors to prevent corrosion or a short circuit. For this purpose, the splice area is often enclosed in a splice case that is formed from two trough-like half shells with separate end plates or seals. Different end seals are used to accommodate different diameter cables and splice cases of different dimensions.
While end seals have been proposed which have many different designs and configurations, one disadvantage they have in common is that it is cumbersome and time-consuming to add or remove a cable. For example, U.S. Pat. No. 5,258,578 (Smith et al.) discloses an end seal that is adapted to seal the space between the cables and the splice case to restrict fluid transfer through the seal. The seal is formed from a body of an elastic, flexible material such as a gel having self-adhesive properties. The body comprises a core portion and a tail portion. The core portion has a shape corresponding to the ends of the splice case and includes cylindrical openings through which the cables extend. The openings are exposed at the outer peripheral surface of the core. The body of the seal also includes a tail portion that is integral with, and extends from, the surface of the core portion. The tail portion has a length sufficient to wrap about the outer peripheral surface of the core to cover all the cylindrical openings. The openings are generally smaller than the diameter of the cables to be placed therein so that the elastic core must expand for the openings to accommodate the cables. When wrapped around the core, the tail seals the portion of the cable between the core and the inside surface of the ends of the splice case. One limitation of this end seal is that, whenever it is removed from a splice case, the seals formed between the core and the cables extending through the openings in the core are disturbed, and therefore the cables must be repositioned upon re-installation of the end seal.
Another proposed type of end seal is formed from two or more segments that mate with a centrally located support structure. End seals of this type are shown, for example, in U.S. Pat. No. 4,692,565 (Koht et al.). The segments contain one or more apertures for receiving a cable. When a cable must be added, removed or changed, it is thus only necessary to remove the segment containing the given cable without disturbing the remaining segments. However, the segments, which surround and abut the support structure, are not fastened to the support structure. Rather, the segments and the support structure are held together by the forces exerted upon them by the splice case itself. Accordingly, when one segment is removed from the splice case, the remaining segments and the support structure will not necessarily remain in place.
Another segmented end seal is disclosed in U.S. Pat. No. 5,825,961 (Wilkins et al.). A similar type of end seal is disclosed in a PSI Telecommunications Inc. catalog entitled “2-Type Closure System” (1990). In this type of end seal, the segments are secured to the support structure by a pair of bolts. While this arrangement prevents the individual components of the end seal from easily separating from one another, it makes it difficult to remove a single segment, since two bolts must be removed.
Another problem with many existing end seals is that they do not have a plane of symmetry, and are therefore not reversible. As a result, two different end seals must be made for use in a conventional splice tray, and these end seals cannot be used interchangeably. This adds to the manufacturing costs, and also complicates the use of these end seals in the field.
There is thus a need in the art for a segmented end seal in which the segments can be easily attached to, and removed from, the support body with a minimum of additional hardware, yet which can be adapted to provide a desired pressure distribution (e.g., an even pressure distribution) across a particular segment. There is also a need in the art for a segmented end seal in which the segments can be independently removed without disrupting the remaining segments or existing seals between the end seal and any cables inserted therein. There is further a need in the art for an end seal which has a plane of symmetry such that the end seal is reversible, and can be used for either side of a splice case.
These and other needs are met by the present invention, as hereinafter described.
SUMMARY OF THE INVENTION
The present invention provides a segmented end seal in which the segments interlock with the support structure so that only a single fastener is needed to fix a given segment to the support structure. This result is achieved by providing the segments with tabs that are inserted into notches located in the support structure. The tabs are oriented with respect to one another such that they must be inserted and removed from the notches in a particular sequence. Typically, the tabs are oriented so as to provide an even distribution of pressure across the segment, but they can also be oriented so as to provide an unequal distribution of pressure across the segment if such is desired. The end seal is preferably constructed with a plane of symmetry such that the end seal is reversible and can be used in either side of a conventional splice case.
In accordance with one aspect of the invention, an end seal is provided for sealing the space between at least one cable and a closure. The end seal includes a centrally located support structure having a plurality of radially extending members, each member being defined by spaced, opposing end faces and an outer peripheral surface. Each of the radially extending members has first and second mating surfaces and a notch located in the first and second mating surfaces. The first and second mating surfaces are connected to, and extend between, the end faces of their respective radially extending members. The end seal also includes a plurality of segments having spaced, opposing end faces. The plurality of segments each interlock with the support structure so that each of the end faces of the segments extend in a common plane with one of the end faces of the support structure. Each segment includes an outer peripheral surface and first and second end surfaces connected to, and extending between, the end faces of the segment. The first and second end surfaces have first and second tabs, respectively, which extend therefrom. The first and second tabs are insertable in first and second notches, respectively, which notches are located in adjacent, radially extending members of the support structure. The first and second tabs of at least one segment are arranged so that they must be inserted in the first and second notches, respectively, in a prescribed sequence so that the segment interlocks with the support structure. At least one aperture extends between the opposing end faces for receiving a cable. The aperture is formed, at least in part, from a semicylindrical surface located in one of the segments.
In some embodiments of the present invention, the apertures in the end seal are provided with a plurality of fingers which extend from the inner surface of the aperture to the interior thereof. The fingers are constructed (e.g., out of a semi-rigid plastic such as polyethylene) so that they are deformed when a cable is inserted into the aperture, thereby providing an initial
3M Innovative Properties Company
Dinkins Anthony
Fonseca Darla P.
Mayo III William H.
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