TWO-LOOP SLING, METHOD AND DEVICE FOR ITS MANUFACTURE Russian patent published in 1997 - IPC

FIELD: manufacture of self-tightening slings from rolled wire. SUBSTANCE: two-loop sling 1 of continuous string with terminated ends is made of flexible material gathered into strand in the form of closed spiral with turns 2 and 3 of different size. Each turn of the spiral is pear-shaped. The first end of the string is connected with the string at the place of formation of closed single string spiral and the second end of the string is fastened to the strand. The method of manufacture of two-loop flexible-material sling involves winding of string loops onto multi-element mandrel, tightening loop on the mandrel, cutting off the string and fastening the ends of the string. The first end of the string is terminated off after formation of two-turn single-string spiral by connecting it to the string, thus closing the spiral. Strand is formed of the strings by rotating closed two-turn single-string spiral on the mandrel simultaneously with mutual movement of turns from one groove of the mandrel to the other. The second end of the string is fixed after formation of the strand and cutting-off of the string. Device intended for manufacture of two-loop sling and having string guide, string twisting and tensioning mechanisms is provided with upright with guides and mandrel having three members: main wheel with two peripheral grooves and shaft secured to the upright, and two additional wheels of different diameters. The additional wheels are provided with one groove each and are mounted on movable member installed in guides of the prop. EFFECT: improved quality of sling and reduced labor input into sling manufacture. 8 cl, 13 dwg