Assembly for pile yarn tension and yarn break detection has number of elastic springs for yarn guide eyelets and light beams which are cut by their upper ends on yarn break for automatic loom stop

摘要

An apparatus to monitor pile yarn tension and breakage, at a loom for weaving patterned double velvets, has an assembly of horizontal and parallel guides under a grid of fixed and parallel bars. The guides are separated by gaps, with vertical elastic springs through them in rows, with their lower ends secured to a support mounting and their upper ends at the eyelets. The apparatus to monitor pile yarn tension and breakage, at a loom for weaving patterned double velvets, has an assembly of horizontal and parallel guides (11) under a grid (5) of fixed and parallel bars. The guides are separated by gaps (19), with vertical elastic springs (21) through them in rows, with their lower ends (24) secured to a support mounting (12) and their upper ends (22) at the eyelets. Each eyelet (23) carries a pile yarn (3), to be held normally at a level over the guide assembly (11). The optical monitor system gives light beams (27) parallel to the guides (11), to detect the presence of any eyelet (23) which has been released by a broken pile yarn (3) and automatically stop the loom. The guide assembly (11) has alternating guides at upper and lower height levels in a crenellated structure, with the light beams (27) passing through the indentations, and between two successive rows of elastic springs (21). The upper end of each elastic spring (21) has a member (22) which cuts through a light beam (27) in the event of a pile yarn (3) break at its eyelet (23). The light beams (27) are generated by laser units. The height (F2) of the guides (11) is controlled, to be moved up and down in relation to a fixed frame, to set the height level of the yarn break detection action. The height level (F1) of the lower support (12), for the lower ends of the elastic springs (21), is adjusted up and down in relation to the fixed frame, to set the tension applied to the pile yarns (3). The optical detection system is linked to an electronic unit which is connected to the loom stop control and also to a blinking visual display to indicate a pile yarn (3) breakage.