A method for attaching a pulling device on a metal tube, in particular in the lower of the pulling of metal pipes for coating of electrical cables

摘要

698,044. Pipe joints; wire couplings. BRITISH INSULATED CALLENDER'S CABLES, Ltd. Feb. 8, 1951 [Feb. 9, 1950], No. 3384/50. Class 99 (i). The method of attachment of a hauling line 1, Fig. 1, to one end of a tube 2, such as an aluminium cable sheath, which comprises placing the shouldered end of a draw-bar 3, the shoulder comprising a nut or collar 5, within that end of the tube 2 and symmetrically deforming the latter round the draw-bar' 3 to form a number of internal shoulders that serve as abutments for the nut 5 when the line 1 is placed under tension and to form a central hole or passage through and beyond which the draw-bar projects, and to reduce the effective diameter of the end of the tube on the hauling line side of the draw-bar; the tube may be deformed by radial crimping at three or more equidistant places to produce a tube shape which when seen in cross-section consists of three or more, preferably four, symmetrically lobes 6, Fig. 2, between which the wall of the tube approaches the axis thereof to the desired extent for defining an aperture for the draw-bar. The tube 2, Fig. 1, is drawn off a drum (not shown) by the line 1 that is attached to the draw-bar 3 by a shackle 10 in such a manner as to provide for relative rotation therebetween. After the tube has been unreeled the deformed end of the tube is removed. Over the bared ends of an electric cable 30, Fig. 4, is placed a metal sleeve 32 which has a serrated internal surface and an axial bar 36 threaded into one end, the bar having a tapered extremity that penetrates and expands the cable end to force it into tight contact with the serrations. The outer portion of the bar 36 is enlarged at 40 to engage a recess 42 in the shackle 10 so that the cable may be drawn through the oversize tube 2 after which the end of the latter is crimped in order that the whole may be drawn through a reducing die, not shown, to force the tube into contact with the cable body, the reduced crimped end facilitating entry into the die. In this operation the front 48 of the shackle 10 takes the place of the nut 5, Fig. 1, and the line 1 acts as the draw-bar. Specification 698,043, [Group XXXVI]. is referred to.