Sewing machine with a thread-guiding needle movable to and fro

摘要

The object is to eliminate or at least mitigate known sewing difficulties, such as the sagging of the sewing material during pricking, tension curling, thread wear and the occurrence of faulty stitches. To achieve the object, it is proposed to connect the needle for rotation to a control device, in such a way that, before pricking, it is rotated out of the normal position with the needle eye pointing in the thread-feed or thread take-up direction (direction of advance of the sewing material), so that the thread tension can be reduced during the downward movement back to the normal position and beyond rotatably opposite the direction of rotation of the gripper and movably upwards into the loop-receiving position of the needle and gripper, in order to reduce the pricking force of the needle and therefore the sagging of the material and to move the needle-thread loop towards the gripper and thereby increase the reliability of the grasping of the loop. The direction and amount of the needle rotation can preferably be controlled in dependence on the direction of displacement of the sewing material. The control can be carried out by a sensor monitoring the tilting of the loop, via a stepping motor, in a simple version via a cam-slot/guide-pin arrangement. The subject of the invention is used in sewing machines. <IMAGE>