The present invention while having many uses, is particularly well suited for use in sealing cable connections of the type used in the power distribution industry and is described for convenience herein as directed to such use.
In known core/sleeve assemblies, an insulating elastic sleeve is adapted to be supported on the core, and the core itself comprises a one-piece plastic ribbon which is spirally formed in the shape of a cylinder. This type of assembly is typically referred to by those skilled in the art, as "cold shrink" tubing to differentiate it from polymeric tubing that may be shrunk by the application of heat. In a typical cable splice to be sealed using the core/sleeve assembly described above, two cable ends are connected and the cold shrink tube assembly is slid into position over the cable splice area. The core is then removed, thereby permitting the sleeve to contract, and form a tight fit around the cable splice. In an alternate embodiment, the core itself is generally of a tubular configuration and has a helical groove cut along its entire length. This helical groove permits the core to be spirally unwound from under the sleeve in a continuous strip which is removed through an annular interior area formed between the core and the cable. The sleeve which had initially been radially extended or stretched over the core, returns to the unstretched position as the strip is progressively withdrawn, thereby causing the core to contract around the cable to form a closely conforming, frictionally retained protective covering.
Although, this prior art construction has been used effectively for many years, substantial savings could be realized if the amount of material used for the core can be reduced without compromising its strength, that is, its ability to withstand the compressive forces imposed on it by the elasticity of the sleeve. Further savings results from one-step manufacturing operation, e.g. molding. Accordingly, it is the general object of the present invention to provide a core assembly for supporting a sleeve, that is both light weight and has sufficient structural integrity to retain the sleeve in a stretched configuration. Another object is to provide for such a core to be progressively withdrawable in its axial direction. These objects can be achieved while avoiding the disadvantages of the spiral cores, which are subject to unraveling when accidentally impacted. Another advantage of the present invention is that disposal problems with spirally unwound cores are reduced and potentially eliminated when the present invention is designed to be reusable.