GB694585A - Yarn testing machine - Google Patents

Abstract

694,585. Testing physical qualities of yarn. FIBREGLASS, Ltd. Sept. 26, 1951 [Nov. 22, 1950], No. 28511/50. Class 106 (ii). A yarn-testing machine, particularly for yarn formed from glass filaments, comprises a pair of yarn-supporting rollers b spaced apart in a horizontal line on a frame a, a loadable roller d between the rollers b and movable in a vertical line, a guide roller or rollers i having braking means m, j, k, n, o associated therewith, tractive means p adapted to exert a tension on the yarn r, a vertically movable slide c carrying the loadable roller d and an index finger h operable by the slide c. The roller d is loaded by a weight e carried on the lower end of the slide c, the weight of the slide c being counterbalanced by a weight el. The index finger h is movable over a graduated scale h<SP>1</SP> on the frame a. Method of operation. A length of yarn r, drawn from a reel s, is passed over the guiderollers i and the adjacent supporting roller b, then under the loaded roller d and over the other supporting roller b, the free end being wound on the drum p. With the loaded roller d in its lower position, and the drum p in motion a braking effect is applied to the guide-rollers i to stop them and thus cause the length of yarn between the rollers b to shorten. The resulting increasing tension in the yarn r causes the roller d and its slide c to rise and actuate the index finger h. When the breaking tension for the yarn is reached, the slide c is prevented from falling by a ratchet device t on the slide engaging pawls u on the frame. The breaking tension can then be accurately read from the position of the index finger h on the scale h<SP>1</SP>. If the yarn has only to pass a minimum tensile test, the friction brake is adjusted to allow the yarn to slide past it when subjected to the said tension, the length of yarn between the rollers b then assuming a constant length.