Drive for raschel loom weft thread guide - wherein coupling point of crank lever linkage follows drop form path

摘要

A drive transmission for the weft insertion on Raschel machines with a yarn reserve extending across the full working width of the machine, has a two stage wheel transmission operated by a crank and the coupling point of a connecting lever, driving via an intermediate wheel the thread guide attached to an endless reciprocating toothed belt. The curve followed by the coupling point has a pear-shaped contour with two stops offset to each other by 180 degrees and the max. stroke of the wheel transmission coincides with the greatest length of the curve. Transmission copes with the problem of braking and accelerating forces at the reversal points. The device has great flexibility and the improved drive enables the thread guide to be adapted to the speed of the machine whatever the type of yarn.