Abstract: The combination of a bobbin case assembly and a supply of thread. The bobbin case assembly has a wall structure defining a receptacle for the supply of thread and a thread tensioning assembly on the wall structure including a thread tensioning element. The supply of thread projects from the receptacle and is wrapped at least partially around the thread tensioning element so as to produce resistance to the removal of the thread from the receptacle.

Abstract: A bobbin assembly having a base wall, a center post projecting away from the base wall in cantilever fashion, a peripheral wall assembly which extends at least partially around the center post, a hook assembly and at least one of a) a thread cutting slot and b) a knife edge on the bobbin assembly. At least a part of the hook assembly is rotatable around a first axis to engage a thread and cause an engaged thread to be formed into a loop as an incident of the at least part of the hook assembly rotating around the first axis. The at least one of the a) thread cutting slot and b) knife edge on the bobbin assembly severs a thread which is formed in a loop by the hook assembly as the at least part of the hook assembly is rotated around the first axis in operation, which loop, if constricted, would wrap against the center post.

Abstract: A bobbin basket for use with a rotary loop taker in a lock stitch sewing machine. The bobbin basket has an integrally formed bearing rib formed of synthetic resin affixed to a metallic cylindrical side wall. Thread grooving protection members are inserted into insert housings at specified areas where the needle thread loop slides against the thread pick up and thread cast off notches. The insert housings are self contained on the integrally formed bearing rib.

Abstract: A rotary loop taker for a lock-stitch sewing machine having a detachable loop seizing point and detachable raceway-defining portion. The inwardly facing vertical wall in the middle and final portions of the bobbin case raceway is defined by a replaceable member that in all cases is formed separately from the annular frame. The lower ledge in the middle and final portions of the raceway is defined by a member that may be formed separately from the annular frame, or may be formed integrally with the frame. In the preferred embodiments of the rotary loop taker, the two members referred to may both be formed integrally with the detachable loop seizing point, or only the member that defines the vertical wall may be formed integrally with the loop seizing point. If desired, neither of the two members mentioned may be formed integrally with the detachable loop seizing point.

Abstract: A polymeric bobbin basket having an increased mass with a partial undercut to engage a latching mechanism on a bobbin case. A dissimilar material of greater strength and fatigue resistance than the polymeric material used in the center post is embedded within the interior of the center post less than the full extent of the center post in an arrangement that absorbs vibration and increases the strength and fatigue resistance of the center post. A shoulder spacing between the materials form the undercut.