Abstract: A thread supplying device includes a rotator feeding a thread downstream of a thread supply path, the rotator winding a periphery thereof the thread several times and locating in the path extending from a thread supply part to a needle and loopers, a stepping motor continuously drivingly rotating in one way the rotator in synchronism with the main shaft of a sewing machine, thread feed setting means setting a unit thread feeding amount necessary for formation of seams per stitch, and control means automatically controlling the rotation of the motor to feed the unit thread feeding amount set by the setting means for each formation of seams per stitch. This device can stably supply a predetermined amount of the unit thread, and achieve stabilization of stitch performance, irrespective of the type of the thread, and whether the feed of a fabric increases or decreases by a rapid change in the rotational speed of the sewing machine.

Abstract: A thread supplying device includes a rotator feeding a thread downstream of a thread supply path, the rotator winding a periphery thereof the thread several times and locating in the path extending from a thread supply part to a needle and loopers, a stepping motor continuously drivingly rotating in one way the rotator in synchronism with the main shaft of a sewing machine, thread feed setting means setting a unit thread feeding amount necessary for formation of seams per stitch, and control means automatically controlling the rotation of the motor to feed the unit thread feeding amount set by the setting means for each formation of seams per stitch. This device can stably supply a predetermined amount of the unit thread, and achieve stabilization of stitch performance, irrespective of the type of the thread, and whether the feed of a fabric increases or decreases by a rapid change in the rotational speed of the sewing machine.

Abstract: An interlock stitch sewing machine for blindstitch hemming with a slippage preventing device is provided which is so constructed as to prevent slippage that is likely to occur due to a position error of a lower fabric portion of the fabric portions stacked by a top-stitching at the fabric end, or a locally deformed portion due to a cutting error, in the blindstitch hemming of a tubular article such as T-shirts or underwear. A top-stiching width guide and a fabric edge guide are oppositely disposed in front of a needle location. A slippage detecting sensor that detects the edge position of the lower fabric portion to detect the presence of slippage, is attached to the fabric edge guide. When the slippage quantity detected by the sensor exceeds a permissible slippage quantity, it is determined there is possibility of slippage, and an informing means is operated.

Abstract: Provided is a faulty sewing detector that is, for example, mounted on an overlock sewing machine, with which an over-edge chain stitch is made in a state in which a body fabric and a sleeve fabric of a T shirt or underwear are overlapped with each other. The detector comprises a fabric twisting detecting sensor that detects a fabric twisting by determining the number of overlap of fabrics sewed which is disposed at a position corresponding to the fabric sewing area of a needle, and, behind a needle location in a sewing direction; a faulty sewing judging means that compares a fabric twisting quantity detected by the sensor, with a preset permissible fabric twisting quantity, to judge it as faulty sewing when the former exceeds the latter; and an informing means that is activated when judged as faulty sewing.