Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Patent
1991-11-26
1993-12-21
Weston, Caleb
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
156 86, B32B 3126
Patent
active
052717828
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a method and article for environmental sealing, particularly of a cable splice, especially a telecommunications cable splice.
Where two or more cables are spliced together, portions of cable jacket will have been removed in order to gain access to the conductors of each cable that are to be electrically (or, in the case of optical cables, optically) connected together. It will then be necessary to make good the area bare of cable jacket if moisture, dirt, insects or other environmental agency is not to impair working of the cable. This making good is generally done by building a so-called splice case around the cable splice, often by first installing a liner which offers mechanical protection and then dimensionally-recovering a dimensionally-recoverable sleeve around the liner. The recovered, generally heat-shrunk, sleeve engages the cables either side of the splice thereby forming a sealed enclosure.
The sleeve may be internally coated with a heat-activatable sealing material, particularly a hot-melt adhesive, and a single heating step may then cause heat-shrinkage of the sleeve and activation of the sealing material, thereby forming a bond to the cables.
In many instances, for example where room for installation of a sleeve is restricted, or where ends of the cables are inaccessible (e.g. where a cable splice is being repaired or modified and some conductors remain joined), a simple tubular sleeve may be difficult or impossible to use. For such applications "wrap-around sleeves" have been developed. They are heat-shrinkable sheets which can be wrapped around a cable splice or other substrate to form a generally tubular shape, and which in general are provided with fastening means for holding them in the wrapped around configuration during heat-shrinkage. In a preferred design such sleeves have ridges (of any suitable shape) at opposing longitudinal edge portions over which a channel, C-shaped in transferse cross-section, can be installed. Reference may be made to GB1155470 and EP0116392, both Raychem.
Heat-shrinkable sleeves have been successfully employed in many fields, but problems may arise when two or more substrates (such as cables, pipes or other supply lines) have to be sealed at one position. This problem, which is known as "branch-off" or "branch-out" may occur where one cable is spliced into an intermediate portion of another cable, or where three or more cables are spliced together. In particular it may occur at an end of heat-shrinkable sleeve in the production of a cable splice case.
A solution to this problem is disclosed in GB1604986 (Raychem) in which a clip is used to form at least two conduits at the end of a heat-shrinkable sleeve by positioning the clip over the end of the sleeve to bring together between the cables circumferentially-spaced portions of the sleeve.
The clip of GB1604986 comprises two or more outer elongate legs and at least one inner elongate leg, at least Dart of the surface of the inner leg being provided with a heat-activatable adhesive or sealant thereon, the legs being so arranged that the clip can be positioned on the open end of a heat-shrinkable sleeve, with the outer legs outside the sleeve and the inner leg inside the sleeve, so as to form at least two terminal conduits capable of receiving elongate substrates.
The clips disclosed in GB1604986 perform excellently and have been widely used throughout the world. Nonetheless, proposals have been made to reduce the likelihood of substrate damage in unfavourable conditions due for example to unskilled hands applying to much heat and perhaps causing an over-hot inner leg to be forced against the substrates.
To solve that potential problem, it was proposed in EP0110705 (Raychem) that a clip should be used that comprises at least two outer legs and an inner leg so arranged that the clip can be positioned over the outer surface of a recoverable sleeve at an end thereof with the outer legs outside the sleeve and the inner legs inside the sleeve; the inner leg comprising a heat-activata
REFERENCES:
patent: 4298415 (1981-11-01), Nolf
Nolf Jean-Marie E.
Read Michael R.
Wambeke Alain
Burkard Herbert G.
N.V. Raychem S.A.
Weston Caleb
Zavell A. Stephen
LandOfFree
Environmental sealing does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Environmental sealing, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Environmental sealing will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-306083