Multi-needle chain stitch sewing machine has a mechanism to move needles selectively at the needle beam, between active and inactive settings, to give an increased range of stitched patterns

摘要

The multi-needle chain stitch sewing machine has a system to position one or more needles (31) between two settings. In the first position, the material is stitched and, in the second position, the needle(s) do not penetrate into the fabric (28). A unit is between the two needle settings to knot the upper and lower threads and/or a cutter to sever the upper and/or lower threads. The multi-needle chain stitch sewing machine has needles with adjustable needles at the edges and/or the center of the needle beam (34), or adjustable needles alternate with fixed needles along the needle beam. The adjustable needles are set by a drive (39) as a pump and a linear motor (40), using a pressure medium which is not compressible e.g. a hydraulic or pneumatic medium. A linear motor is between two adjustable needles. The needle setting drive can also be an electromechanical system, especially as a rack with a pinion powered by an electromotor. The thread cutter is a cutting blade, at the looper hooks or at the spreader at a pair of needles. A fabric movement system is at the fabric support, which can move the material in two directions. An independent claim is included for a technique to stitch a pattern in fabrics with a multi-needle chain stitch sewing machine. At the end of a stitch, and preferably at the end of a stitched pattern, at least one needle is moved from an active setting into an inactive position where it plays no part in the next stitch or stitched pattern. The upper thread is secured to the lower thread to prevent the final stitch opening spontaneously when the needle setting is changed. Preferred Features: The upper thread is knotted to the lower thread at least before the start of the next stitched pattern. The upper and/or lower thread is cut before the start of the next stitched pattern. The fabric is moved in the sewing direction, at least before the start of the next stitched pattern, to draw out and extend the upper thread from the thread supply, before it is knotted with the lower thread and/or severed. A number of needles are moved simultaneously from the first setting into the second position, at least at one needle beam.