Abstract: A thread routing mechanism for needle-switchable type sewing machine is installed on a needle bar switching mechanism of the sewing machine, and includes a thread take-up lever, a cylindrical needle bar case and a plurality of threads. The thread take-up lever includes a sway control end and a thread take-up end having thread holes. The cylindrical needle bar case has a rotation axis and a plurality of spaced needle bar holes, and internally defines a hollow space. The needle bar holes are equally distant from the rotation axis, and each receives a needle bar therein. The needle bars respectively carry a needle having an eye formed thereon. The threads are separately routed through a thread course defined by the thread holes, the hollow space and the needle eyes, such that the length of the threads in the thread course maintains same without being affected by a needle bar switching operation.

Abstract: There is provided a needle thread tension controller that can control a magnitude of tension on a needle thread for each stitch, that can draw the needle thread with a slim chance of occurrence of a thread break, that easily, accurately detects occurrence of the thread break when the thread break has occurred, and that does not cause any excess or deficiency of a quantity of accumulated thread, which would otherwise be caused by drawing a needle thread. There are provided an upstream grip section 40 and a downstream grip section 60 for gripping a needle thread and a turning section 80 for turning the needle thread. In a torque control zone, rotating force is imparted to a turning arm in accordance with a torque value.

Abstract: A thread taking-up tool is attached to a needle bar sticking out of a sewing machine head, and its leading end has a plurality of thread holes. The thread holes of the thread taking-up tool are arranged in the lateral direction. A thread handling body has a cam face in the vertical direction. Needle threads from a tension device to needles are controlled by the vertical motion of the thread taking-up tool and the action of the cam face of the thread handling body. When the needles ascend from the lowest position, an endless hook attached to the thread taking-up tool is engaged with the left needle thread between the cam face lower end and the thread hole of the thread taking-up tool. Each thread is handled in with the left needle thread staying at the cam face lower end, so that the needle thread loop at the remotest end is absorbed surely.

Abstract: A new thread control mechanism including a second movable needle thread control secured to the upper end of the needle bar from which the thread extends to the needles, a first movable needle thread control eyelet operatively connected to the needle bar such that it reciprocates vertically in synchrony with the first movable needle thread control, and stationary needle thread eyelets adjustably mounted on the exterior of the sewing machine through which needle thread extends to said first movable needle thread eyelets.

Abstract: A sewing machine has a bed housing having a needle penetrating hole at one end thereof, an arm housing rising from the other end of the bed housing and extending to the one end of the bed housing over the bed housing, a laterally-long needle bar arm rotatably held in the arm housing and having a needle at the front end thereof, and a drive unit for swinging the needle bar arm with respect to the bed housing accommodated in the bed housing. The arrangement of the laterally-long needle bar arm and the drive unit accommodated in the bed housing, can effectively reduce the overall height of the sewing machine. It further reduces the weight and cost of the sewing machine, since no conventional material, such as cast iron having a heavy weight is used and die cast aluminum associating with a higher cost, may be employed for producing the arm housing.

Abstract: The present invention relates to an attachment for a sewing machine, and more particularly to an overcasting attachment for use with a lockstitch sewing machine which is prepared for straight stitching, wherein needle-like thread guide pieces are provided for passing an additionally prepared thread or threads from sideways around the needle point at a suitable time, making use of the vertical reciprocating movement of the needle, so as to engage the thread or threads with the sewing machine threads for straight stitching.

Abstract: Opposing plates of a thread tensioning device for use on a lock stitch sewing machine in a thread handling system wherein needle thread is caused to pass between elongate members of a thread holder which meters thread to the looptaker of the machine are formed with recesses through which the thread can fall without restraint to supply thread to the looptaker during the movement thereof from a loop seizing to a cast-off position.

Abstract: A lock stitch type hand sewing machine comprises a bed and a needle arm pivoted mutually at one end on the bed. The bed is provided with a shuttle and the needle arm is provided with a needle on its free end. The operation of this sewing machine is effected by gripping the bed and the needle arm with one hand to rock them, and according to this operation, the needle and the shuttle are relatively moved to form lock stitch.

Abstract: A needle thread control mechanism for sewing machines which permits a machine operator to adjust the stitch tightness includes a thread take-up mechanism arranged wholly outside of the machine frame and a thread controlling mechanism arranged directly between the needle thread take-up mechanism and a thread supply source. A thread controller, adapted to cooperate with the thread take-up mechanism, is also provided.

Abstract: A thread handling device is disclosed in a type 301 lockstitch rotary hook loop taker sewing machine having a three-to-one hook to arm shaft ratio for controlling and metering slack needle thread prior to needle penetration to prevent the thread from wrapping around the point of the needle, which could prevent loop seizure, break the thread, or interfere with correct stitch formation. The thread is guided between two stationary members, with the controller between the members, the controller comprising an edge attached to the needle bar drive connecting link, moving with it, and only engaging the thread as the take-up and needle bar descend, providing a lengthened thread path prior to needle penetration.

Abstract: This disclosure relates to threading apparatus for sewing machines and in particular to a movable thread engaging means disposed in proximity to a disc-type tension device which thread engaging means is operative during movement of the tension discs towards one another for guiding the thread between and in operative relationship with the tension discs so as to ensure that the thread will be properly threaded through the tension device.