Patent ID: 7036443

Claim:
A gripper hook in a lock stitch sewing machine, in which the sewing machine comprises a vertically mounted needle for an upper thread, a stitch plate, below the stitch plate a housing which accommodates said gripper hook, substantially formed into an open cylinder and rotatably mounted on a horizontal axis, a bobbin basket which is concentrically supported inside the gripper hook and is designed as an open cylinder for receiving a bobbin case, the bobbin case housing a bobbin for an under thread and the needle in executing a stitch being brought down perpendicularly to the axis of the rotary gripper hook in front of the open part of the gripper hook through an opening in the wall of the bobbin basket so that a gripper hook tip catches the upper thread and leads the upper thread around the bobbin basket, thereby forming a stitch by interaction with the under thread when the needle is brought back up, wherein the gripper hook has a cylindrical side wall which is at least wide enough for the side wall to protect the bobbin basket from being struck by the needle in a situation in which the needle is brought downwards when a force is pressing the tip of the needle out of an alignment in which it normally runs.