| 摘要 |
<p>PURPOSE: To obtain a pipe which reduces the friction of a cable covering by a method wherein a nearly square shape as viewed from a plane is made of an inorganic rigid material, a single through hole or a plurality of through holes are made in two outside faces, uneven parts are formed in proper positions on inner circumferential faces of the through holes, the inner circumferential faces come into point contact with the cable covering and contact areas are reduced. CONSTITUTION: A nearly square shape as viewed from a plane is made of an inorganic rigid material, and four through holes 5 are made in two outside faces 3, 4, and uneven parts 6 are formed on inner circumferential faces of the through holes 5. Thereby, even when the inorganic rigid material is earthenware or cement, the rough inner circumferential faces come into point contact with a cable covering, contact areas are reduced, and an action that the friction of the cable covering is reduced is obtained. As a result, the cable covering is not damaged due to frictional heat as different from conventional cases in a pulling-into operation in which a cable is inserted into, and passed through, a pipe for cable burying.</p> |
