Crossing device for the production of non-fraying edges of a double woven fabric on a double-rapier loom

A method for the manufacture of non-fraying edges (168, 170) of a double-woven fabric (154) on a double-rapier loom using a double-shed crossing device for an upper shed (108) and a lower shed (106), said crossing device comprising per shed (106, 108);

• a needle carrier (98, 118) with at least one elongated stationary needle (100, 120), said stationary needle (100, 120) having two ends, one end of which, the fastening end, being fixed to said needle carrier, the other, free end being provided with a needle eye for the guidance of a stationary thread (130, 142), said needle carrier (98, 118) being movable between and first end position and a second end position;
• a slot plate (102, 110) with at least one oblique slot (104, 112) for the guidance of a crossing thread (138, 148), said slot plate being movable between a first end position and a second end position;
• a positioning device (122, 126) with at least one eye for the positioning of said crossing thread (138, 148) in the respective oblique slot (104, 112) of said slot plate (102, 110) for the changeover of said crossing thread (138, 148) relative to an associated stationary thread (130, 142) by a corresponding shift of said positioning device (122, 126) relative to said slot plate (102, 110), said positioning device (122, 126) being movable between a first end position and a second end position;
• the method comprising the steps of:
• (A) moving said needle carrier (98, 118) and said slot plate (102, 110) in their respective first end positions with said positioning device (122, 126) being in one of its first and second end positions, said needle carrier and said slot plate thereby defining a first shed positioning of said crossing device, in which first shed positioning said crossing threads (138, 148) are guided passed said stationary needles (100, 120) between said free ends and said fastening ends thereof;
• (B) keeping said crossing device in said first shed positioning for a time period;
• (C) inserting a weft in one of said upper shed (108) and said lower shed (106) during said time period and subsequently inserting a weft in the other of said upper shed and lower shed during said time period;
• (D) moving said positioning device (122, 126) from said one end position to the other of its first and second end positions during said time period for preparing a changeover of said crossing threads (138, 148) in relation to said stationary threads (130, 142) in the respective shed;
• and
• (E) moving said needle carrier (98, 118) and said slot plate (102, 110) in their respective second end positions after elapse of said time period, thereby defining a second shed positioning of said crossing device, in which second shed positioning said cross threads (138, 148) are guided outside of the region of said stationary needles (100, 120) and thus are changing over in relation to said stationary threads (130, 142) in the respective shed (106, 108) due to said positioning device (122, 126) being in its other end position.