Patent GB-1466998-A (GB)
Title: Winding method and apparatus
IPC: E04G21/12
Filed: 1972-11-10
Abstract: 1466998 Winding pipe reinforcement GKN BUILDING SUPPLIES & SERVICES Ltd 31 Jan 1974 [10 Nov 1972] 51981/72 Heading F2P [Also in Division B8] To provide an article with a tensioned, helical winding, a tendon or a flexible elongated member is helically wound on the article to provide an initial winding, the tendon and the member if provided are engaged in a feeding device, one tendon end is enclosed to the article, and the device is moved helically about the article while feeding the tendon and the member if provided through the device so that the tendon is wound on to the article under a controlled tensile load reacted by the frictional force between the initial winding and the external surface of the article. As shown, Fig. 1, the apparatus comprises frame 12 mounted on article 10 and having rings 13, 14 connected by bar 15 and three rods 16 carrying grooved support rollers 17, 18. Bar 15 carries grooved pulleys 20, 21 tangential to the article, Fig. 2, and pulley 24 slidable along the bar by hydraulic rams 29, 30. Ram pump 35 is driven by pulley 21. The tendon 11 is initially wound, e.g. by hand, from left to right under little tension, a loop 39 is formed around the pulleys and the end 11 is enclosed to the article. Frame 12 is then rotated on the article, the tendon running about pulleys 20, 24, 21 so that pulley 20 lifts the tendon, pulley 24 urged leftwards by the rams, tensions the tendon, and pulley 20 lays the tendon. The tension is reacted by friction between the initial turns and the article. Grooved rollers 18 engage the tensioned turns to feed the frame along the article. Finally, the tensioned tendon is anchored and redundant initial turns removed. If pulley 24 is urged to the end of bar 15 before completion of tensioning, the tendon is anchored and cut, the initial turns re-anchored, and winding started with pulley 24 withdrawn by the rams. The full tension may be developed during a number of passes of frame 12. The frame may pass in the same direction as the initial winding, or from the ends to the middle of the article. Separate windings may occupy separate parts of the length of the article. The initial turns may be laid in article grooves, the tensioned turns being laid between the grooves. The tensioning device may wind on further initial turns. Pulleys 20, 21 and rams 29, 30 may be replaced by one pulley and one ram, pulley 24 may be replaced by two pulleys to form a rectangular array of pulleys, or pulley 24 may be locked when extended and a second pulley 24 slid by the rams to continue tensioning. Pulley 24 may be conical, so that, with the tendon locked to pulleys 20, 21 loop slack may be wrapped around the retracted pulley 24 before further tensioning. Frame 12 may have a weight to balance the tensioning device. The frame may be counterbalanced for movement along vertical articles. Alternatively, the initial winding may comprise a separate, endless member, e.g. wire rope, whose turns 44, 45, 46, Fig. 3, are wound about the article and about pulley set 41-43 on frame 12. During frame rotation a force 47 tensions loop 48, via movable pulley 42, off-set rollers 41, 43 move the turns sideways with the frame, and roller 41 rotates roller 51 of a set of framemounted rollers 49-52, Fig. 4. Tension 56, fed to the rotating frame and anchored to the article, is wound about the article, a loop 54 of the tendon being tensioned by force 53 via movable pulley 50. Pulley 51 is of smaller diameter than pulley 41 to compensate the stretching of the tensioned tendon. Pulley 41 may have several turns about it. Each pulley set may comprise three pulleys. More than one pulley in each set may be moved for tensioning. Variable gearing may be located between pulleys 41, 51 of the same diameter to compensate for tendon stretch. If loop 54 extends and pulley 50 reaches the end of its travel, pulleys 41 and 51 are locked, and the frame is rotated to shorten the still-tensioned loop. The separate, endless member may be replaced by a separate member wound helically about the whole length of the article, the tendon being laid between the windings of the member. The article may be a pipe, or a cylindrical container comprising concrete stoves bolted to an internal ring and held together by the tendon, e.g. of high carbon steel wire. The article may be of non-cylindrical, e.g. elliptical, crosssection, and may be of varying cross-sectional size, e.g. of frusto-conical shape.