Ringed sheath for passage of cable i.e. electric wire, in building field, has oblong section in which height of rings varies between minimal height in zone having smaller dimension and maximum height in zone having larger dimension

摘要

The sheath has an oblong section in which height of rings varies between a minimal height (h1) in a zone having smaller dimension and a maximum height (h2) in a zone having larger dimension. An effective sectional area of the sheath ranges between 80 and 300 square mm. A smallest outer dimension of the sheath ranges between 8 and 12 mm, and a largest outer dimension (H) of the sheath ranges between 20 and 50 mm. The sheath is made of synthetic material selected from a group consisting of poly propylene, polyethersulfone and high-density polyethylene. An independent claim is also included for a ringed sheath forming installation comprising a pair of molds.