| 摘要 |
<p>A method and a mechanical assembly are disclosed for mounting, on angular areas of a mattress-enveloping bed sheet or similar article, segments of elastic band to elasticize said angular areas. The method requires that the angular transversal seams which unite adjacent flaps of the sheet pairwise by detected by a thickness gauge so as to generate a signal going to a stitch counting assembly (SCA) wherein a preselected number of stitches corresponding to the angular area to be elasticized has been preselected. The sewing machine is thus started and begins to stitch the continuously fed fabric; meanwhile, a double fold is formed on the fabric edge by a specially provided shaping device. Immediately after, the elastic band feeding device enters action and introduce the elastic band in the fabric double fold for a time determined by the Stitch Counting Assembly (SCA) and the sewing machine sews the elastic band and the folded fabric together. As the preselected number of stitches has been applied, the elastic band feeding mechanism is withdrawn, the elastic band is locally twisted and a snipping blade housed in the presser foot of the sewing machine snips the elastic band the cycle is restarted and repeated until all the four corner areas of the bed-clothes article have been elasticized.</p> |
