Needle guard
AssigneeVSM Group AB
InventorRolf Wahlström
Life of this patent
Estimating the term…
Abstract
A gripper hook for a sewing machine. The sewing machine includes a needle, a stitch plate and a housing for the gripper hook. The gripper hook includes an open cylinder and is rotatably mounted on a horizontal axis. A bobbin basket is supported inside the gripper hook receives a bobbin case. The bobbin case houses a bobbin. The needle, in executing a stitch, is brought down perpendicular to the axis of the gripper hook in front of the open part of the gripper hook through an opening in the wall of the bobbin basket such that a gripper hook tip catches the upper thread and leads the upper thread around the bobbin basket. The gripper hook has a side wall that is at least wide enough for the side wall to protect the bobbin basket from being struck by the needle when the needle tip is out of alignment.
Claims9
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.
A method of protecting a bobbin basket from being struck by the needle in the up and down movement of the needle in a lockstitch sewing machine comprising a vertically mounted needle for an upper thread, a stitch plate, below the stitch plate a housing which houses a gripper hook which is substantially formed into an open cylinder and is 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, the method comprising:
- the bobbin basket is designed with a needle support on the uppermost part of the wall of the bobbin basket for supporting the needle in a horizontal direction in the lowest position of the needle and
- the needle support is protected from the needle during the sewing of stitches by a cylindrical side wall of the gripper hook wide enough for the side wall to cover the needle support to such an extent that the needle cannot strike the needle support.
Dependencies are inferred from the claim text.